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