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