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