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