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