I draw in my breaks and at lunch. My commute is about 45 minutes, but it's no use for drawing because the longest single stretch is 20 minutes on the train, and I often don't have a seat. I work on scripts on my phone while travelling, though. I also draw when I get home, but the bulk of the work is done at the weekend.
It's difficult to find time, but luckily I like my job, so it doesn't tend to disrupt my mood or leave me feeling unable to draw. The biggest problem with it is that the heavy computer use can cause my RSI to flare up, so I have to be very careful.