I attended a crafty quilt class given by our local guild, that was just that, using colored pencils (there are certain pencils made for this process, but you might be able to use regular ones. Try it?) to color prequilted quilt square, then using a fabric medium to set the colors. I used the square in a tote bag for my DD. My grand dog Nala loved trying it on for size! Lol! I have even used permanent markers to make a fabric match another better by adding my own color accents. I just coat it with fabric medium after I finish coloring.