So, try this. The youth room walls can be the same color as any other room but you can give the kids a chance to be creative and personalize the room by putting up some wood railings (see my picture) and letting the kids paint wooden plaques to be attached to the rails. They can easily be removed or switched out to allow new kids to participate, kids can work together with a friend or two to design their plaque, and final designs can be approved by the group. Encourage them to show what they believe and who they are!
It's not the cool room that keeps kids coming to church.
It's the cool people!