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