I'm thinking that anything in the Flag area (Inner Basin as AZDude suggested) or up on the Rim would be a good choice. I did See Canyon near Christopher Creek last year on Oct 24th and the colors were just blazing! (check out my pics)......I thought I was back in New England.
Not sure if it's just a tad too early though. Maybe another week for full color.
"May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view. May your mountains rise into and above the clouds" Ed Abbey