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