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