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