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