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