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