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