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