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