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