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