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