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