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