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