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