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