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