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