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