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