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