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