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