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)(30,38,40,39)(9,11,15,24)(10,16,20,31)(12,25,27,22)(13,23,14,29)(17,30,33,40)(18,21,19,35)(26,39,28,38)(32,37,34,36)(2,5)(3,8)(6,7)(9,12,14,26,15,27,13,28)(10,17,19,32,20,33,18,34)(11,22,23,39,24,25,29,38)(16,30,21,36,31,40,35,37)(2,6)(5,7)(9,13,15,14)(10,18,20,19)(11,23,24,29)(12,26,27,28)(16,21,31,35)(17,32,33,34)(22,38,25,39)(30,37,40,36)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.