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