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