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