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