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