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