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