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