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