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