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