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