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