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)(11,19)(12,15)(13,22)(14,18)(16,20)(17,23)(21,24)(25,26)(27,30)(28,31)(29,32)(33,40)(34,38)(35,37)(36,39)(9,11,13,12,14,20,23,21)(10,15,17,19,18,24,22,16)(25,27,28,34)(26,30,31,38)(29,33,36,35)(32,40,39,37)(1,3,4,8)(2,5,6,7)(11,20)(12,21)(15,24)(16,19)(26,31)(27,33)(29,36)(30,37)(34,35)(38,40)(9,12,13,20,14,21,23,11)(10,16,17,15,18,19,22,24)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.