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