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