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