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