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