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