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