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