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