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