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