It’s funny to think of Jenny Saville in her studio at 1 am, music blaring, with a vacuum cleaner in hand as she approaches one of her canvases and starts sucking great lines through her work. That it should be a Henry vacuum, the shamelessly anthropomorphized device, makes it even better. As he approaches Saville’s giant works, ready to wreak destruction, his expression will be one of eternal cheerfulness.

“I’m getting more sophisticated with working out how many suction techniques I can find,” says Saville with a laugh as we stand in front of Ebb and Flow. This great tangle of bodies is part of her new show at the Gagosian Gallery in London.

Saville is known as a painter, but this exhibition is of her drawings. It is “massive” freedom, she says, to work in charcoal and pastel rather than oil paint. “Just because of the transparency of drawing, you’ve got the possibility of multiple bodies. It’s an attempt to make multiple realities exist together rather than one sealed image.” It means she can change direction quickly. “In two hours, you can put a leg in here, go right through a body, go right through genitals, one gender changes to another.”

“Some sort of human scribbling,” says Saville. She wore away the skin on her fingers doing it. At her studio, a pile of eraser droppings built up beneath each canvas as she rubbed bits away, but nothing is ever really deleted – the canvas holds the memory of touch.

There is a gentleness to this work that may surprise those who loved the pieces – such as the brazenly meaty Branded – from Saville’s 20s when she was part of Charles Saatchi’s Young British Artists group. Her 2003 show in New York, Migrants, comprised highly charged, even violent images. (Visitors to her studio in past years have noted the graphic pictures she has collected, including those of burn victims and photographs from Abu Ghraib.) “I was almost aggressive [in my work] all the time, whereas now …” She trails off.

I wouldn’t make this work if I were a guy.

“I can’t say I’m wiser; I’m probably more foolish. But I think I’ve accepted that making beautiful things is interesting, whereas before I was not interested in beauty. I was anti-beauty, I would say. I like that something reveals itself slowly; it doesn’t have to shout it. That’s shocked me.” It had children that changed her work. “I find watching them so beautiful that I have accepted that sort of beauty into my life.”

Saville is at her studio in Oxford, where she lives, from shortly after 8 am, and works until about 4 pm, when she goes home to spend time with her two kids; once they are in bed, she’s back in the studio until 1 am. “I love the nights,” she says. Cycling around the city, she likes to look up at students and researchers working in brightly lit science labs on her way to her own night shift.

One Out of Two (Symposium), 2016: charcoal and pastel on canvas

She always knew she would be an artist and assumed she would work as a waitress, as she did at college, to fund her activity. Instead, she was scooped up by Charles Saatchi, who bought her Glasgow School of Arts degree collection and commissioned her to do work for his gallery for the next two years. “Who else was going to give a 23-year-old a huge gallery and say: ‘Yes, you can make a 21-foot triptych?’” she says. “I was lucky I was part of that generation and given a platform to try things out.” It was, she says, “inspiring that these young, state school-educated punky kids had taken over the art world. But it wasn’t this pally club.”