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