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