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