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