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