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