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)(18,20)(22,24)(25,26)(27,33)(28,32)(29,30)(31,35)(34,40)(36,38)(37,39)(9,10,12,14)(11,13,16,15)(19,23)(22,24)(26,30)(28,36)(31,33)(34,37)(9,10)(11,13)(12,14)(15,16)(17,18,21,20)(19,22,23,24)(25,27)(26,31)(28,37)(29,35)(30,33)(32,40)(34,36)(38,39)(1,2,4,5)(3,6,7,8)(9,10)(11,13)(12,14)(15,16)(17,19)(18,22)(20,24)(21,23)(25,28,29,36)(26,32,30,38)(27,34,35,37)(31,39,33,40)(1,3,4,7)(2,6,5,8)(9,11,12,16)(10,13,14,15)(17,20,21,18)(19,24,23,22)(25,26)(27,31)(28,38)(29,30)(32,36)(33,35)(34,40)(37,39)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.