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