The best way to draw and color is to use permanent magic markers and crayons (the non-toxic are not the best for color) so go ahead use the TOXIC CRAYONS ! You don't have to be politically correct all the time.
When you use permanent markers and toxic crayons. It will not crack like paint when you roll it up and it will not smear if it gets wet.
So here you have a great teaching tool. This one is in Russian and English. I've had it about 20 years. It still looks good and it fits in my suitcase nicely. I have carried all over the world.
Next time I am going to use black cloth and more flourescent colorers: chalk,crayons, some paint.