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