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