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