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)(11,17)(12,24)(13,27)(14,19)(15,31)(16,22)(18,30)(20,25)(21,36)(23,33)(26,32)(28,34)(29,40)(35,38)(37,39) involution — undirected(2,5)(6,8)(9,11,14,22)(10,16,19,17)(12,25,23,15)(13,21,29,37)(18,34,35,32)(20,24,31,33)(26,38,28,30)(27,39,40,36)(1,3,4,7)(2,6,5,8)(9,12,15,11,14,23,25,22)(10,17,20,24,19,16,31,33)(13,28,30,37,29,26,38,21)(18,32,27,39,35,34,40,36)(9,13,25,38,14,29,15,30)(10,18,31,40,19,35,20,27)(11,21,12,26,22,37,23,28)(16,32,24,36,17,34,33,39)(2,5)(6,8)(10,19)(16,17)(18,35)(20,31)(24,33)(27,40)(32,34)(36,39) 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.