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