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