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)(11,17,19,14)(12,16,21,23)(18,24,20,22)(25,26,30,36)(27,37,39,32)(28,33,38,35)(29,40,31,34)(9,11,13,19)(10,14,15,17)(12,20,21,18)(16,24,23,22)(25,27)(26,32)(28,31)(29,38)(30,39)(33,40)(34,35)(36,37)(2,5)(6,8)(25,28,29,39,30,38,31,27)(26,33,40,32,36,35,34,37)(1,3,4,7)(2,6,5,8)(10,15)(14,17)(16,23)(22,24)(25,29,30,31)(26,34,36,40)(27,38,39,28)(32,35,37,33)(9,12,13,21)(10,16,15,23)(11,18,19,20)(14,22,17,24)(25,28,31,27,30,38,29,39)(26,35,34,32,36,33,40,37)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.