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