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