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