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