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