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