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