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