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