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