This dragon is designed for people who want an actual coloring challenge. The scales, wing membranes, and muscular detail all reward patience and layering — colored pencils or fine-tipped markers will show off the detail better than broad crayons.
Start with a base color for the scales and work darker in the recesses between each one. The wing membranes look best with a lighter, more translucent feel — try a thin wash of color there while keeping the body scales more saturated.