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