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