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