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