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