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