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)(25,26,31,34)(27,32,36,39)(28,29,33,30)(35,37,40,38)(2,5)(6,8)(9,11)(10,14)(12,18)(13,17)(15,20)(16,21)(19,23)(22,24)(25,27)(26,32)(28,35)(29,37)(30,38)(31,36)(33,40)(34,39) involution — undirected(11,17)(14,20)(18,23)(21,24)(25,28,30,26,31,33,29,34)(27,35,38,32,36,40,37,39)(1,3,4,7)(2,6,5,8)(10,15)(14,20)(16,22)(21,24)(27,36)(32,39)(35,40)(37,38)(9,12,13,19)(10,16,15,22)(11,18,17,23)(14,21,20,24)(25,29,31,30)(26,33,34,28)(27,37,36,38)(32,40,39,35)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.