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