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