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