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)(14,19)(15,20)(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)(10,16)(12,21)(13,22)(14,30)(15,23)(17,29)(18,31)(19,32)(20,33)(24,35)(25,26)(27,37)(28,39)(34,38)(36,40)(1,3,4,8)(2,5,6,7)(9,11)(10,17)(12,25)(13,30)(14,22)(15,23)(16,29)(18,35)(19,33)(20,32)(21,26)(24,31)(27,37)(28,39)(34,36)(38,40)(9,12,13,27,15,26,14,28)(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.