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