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