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