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