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