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