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