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