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)(11,20)(12,21)(13,19)(14,18)(15,17)(16,22)(23,24)(25,26,28,31)(27,33,35,30)(29,32,37,40)(34,39,36,38)(1,3,5,4)(2,6,8,7)(9,11)(10,16)(12,17)(13,21)(14,22)(15,24)(18,20)(19,23)(25,27)(26,30)(28,35)(29,34)(31,33)(32,38)(36,37)(39,40)(9,12,13,16,14,23,15,20)(10,11,17,24,18,22,19,21)(27,34)(29,37)(30,38)(32,40)(33,39)(35,36)(1,4,5,3)(2,7,8,6)(9,13,14,15)(10,17,18,19)(11,21,22,24)(12,20,23,16)(26,31)(30,33)(32,40)(38,39)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.