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