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