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