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