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