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