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