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)(27,31)(28,36,37,40)(29,34)(30,33)(32,35,39,38)(1,2,4,5)(3,7,8,6)(9,11,12,18)(10,14,15,17)(13,19,20,21)(16,22,23,24)(25,27,30,29)(26,31,33,34)(28,35,37,38)(32,36,39,40)(10,15)(13,20)(14,17)(19,21)(25,28)(26,32)(27,35)(29,38)(30,37)(31,36)(33,39)(34,40) involution — undirected(1,3,4,8)(2,6,5,7)(11,18)(14,17)(19,21)(22,24)(26,33)(31,34)(32,39)(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.