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