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