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