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