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