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