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