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