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)(11,16)(12,21)(13,20)(14,18)(15,19)(17,22)(23,24)(25,26,30,34)(27,31,28,36)(29,38,39,33)(32,35,40,37)(2,5)(6,8)(9,11,15,21)(10,16,19,12)(13,17,14,24)(18,23,20,22)(25,27,30,28)(26,31,34,36)(29,37,39,35)(32,33,40,38)(3,7)(6,8)(9,12,15,16)(10,17,19,24)(11,20,21,18)(13,23,14,22)(25,28,30,27)(26,32,34,40)(29,35,39,37)(31,38,36,33)(1,3,4,7)(2,6,5,8)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.