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