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