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