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