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