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