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