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