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