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