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