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