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)(11,13)(12,14)(15,16)(17,18,21,19)(20,22,24,23)(25,26)(27,34)(28,32)(29,37)(30,31)(33,38)(35,39)(36,40)(10,11)(12,16)(17,18)(19,21)(20,23)(22,24)(25,27,31,28)(26,32,30,34)(29,35,38,36)(33,39,37,40)(10,11)(14,15)(18,19)(22,23)(25,28,31,27)(26,32,30,34)(29,35,38,36)(33,40,37,39)(1,2)(3,5)(4,6)(7,8)(9,11,13,10)(12,14,16,15)(17,19,21,18)(20,22,24,23)(25,29)(26,33)(27,35)(28,36)(30,37)(31,38)(32,39)(34,40)(1,3,4,7)(2,5,6,8)(9,12)(10,14)(11,15)(13,16)(17,20)(18,22)(19,23)(21,24)(25,30,31,26)(27,32,28,34)(29,33,38,37)(35,40,36,39)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.