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