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