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