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