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