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