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