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