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