In April of 2006 The American Physical Society published a coloring book of famous physicists. The images are all available for downloading at www.physicscentral.com/coloringbook.
You can download the Feynman page directly by going to http://www.physicscentral.com/coloringbook/feynman.pdf.
The Friends of Tuva has had a couple of experienced coloring experts (Lauren, age 6, and Lisa, age 4.5) try these pages out, and the verdict given was “A+”!
Try these out for yourselves and see if you know any young people who would be interested!