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