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