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