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