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