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