I just do a hobo-wash in the stalls at school. Sadly, this is a satellite campus, so there are no athletic facilities to take advantage of. I shower before I leave, use powder, baby wipes, deodorant, and a small towel to clean up as I change from bike gear to street clothes. As for hair, nobody expects grad students to look too nice (especially not my variety), so I tend to get away with wearing a ball cap, but I imagine that's not an option at work for you.