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