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