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