One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10,15,21,16,22,14,20)(11,23,12,26,25,18,28,17)(13,19,31,36,32,37,30,35)(24,38,27,39,29,34,40,33)(1,3,4,7)(2,5,6,8)(9,11,16,25)(10,17)(12,15,28,14)(13,24,32,29)(18,21)(19,33)(20,23)(22,26)(27,31,40,30)(34,36)(35,38)(37,39)(9,12,15,25,16,28,14,11)(10,18,20,26,22,23,21,17)(13,29,31,40,32,24,30,27)(19,33,35,34,37,39,36,38)(2,6)(5,8)(9,13,14,30,16,32,15,31)(10,19,20,35,22,37,21,36)(11,24,12,27,25,29,28,40)(17,33,23,38,26,39,18,34)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.