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