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