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