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