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