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