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