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