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