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