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