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