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