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