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