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