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