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