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