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