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