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