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