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