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