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)(11,15)(12,14)(13,16)(17,18)(19,23)(20,21)(22,24)(25,26,30,33)(27,28,34,31)(29,37,38,32)(35,39,40,36)(1,2,5,6)(3,8,7,4)(9,10,12,14)(11,15,16,13)(18,20)(19,24)(27,34)(28,31)(35,40)(36,39)(2,6)(3,7)(9,10,12,14)(11,13,16,15)(17,18,21,20)(19,23,24,22)(25,27)(26,31)(28,33)(29,35)(30,34)(32,39)(36,37)(38,40)(1,3,5,7)(2,4,6,8)(9,10)(11,13)(12,14)(15,16)(17,19,21,24)(18,22,20,23)(25,28,30,31)(26,27,33,34)(29,36,38,39)(32,35,37,40)(1,4)(2,7)(3,6)(5,8)(9,11,12,16)(10,13,14,15)(17,20,21,18)(19,23,24,22)(25,29,30,38)(26,32,33,37)(27,35,34,40)(28,36,31,39)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.