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