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