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