One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,3,7,4,6,8,5)(9,10)(11,21,24,35)(12,17)(13,18)(14,19)(15,20)(16,23,31,29)(22,37,25,36)(26,32)(27,33)(28,34)(30,39,40,38)(9,11,15,24)(10,16,20,31)(12,25,28,22)(13,23,14,29)(17,30,34,40)(18,21,19,35)(26,39,27,38)(32,36,33,37)(2,5)(3,8)(6,7)(9,12,14,27,15,28,13,26)(10,17,19,33,20,34,18,32)(11,22,23,38,24,25,29,39)(16,30,21,36,31,40,35,37)(2,6)(5,7)(9,13,15,14)(10,18,20,19)(11,23,24,29)(12,26,28,27)(16,21,31,35)(17,32,34,33)(22,38,25,39)(30,36,40,37)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.