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