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)(11,15)(12,14)(13,16)(17,18,20,22)(19,21,23,24)(25,26)(27,28)(29,37)(30,31)(32,33)(34,38)(35,40)(36,39)(1,2,5,6)(3,4,7,8)(11,16)(13,15)(19,23)(21,24)(26,31)(27,33)(29,38)(36,40)(2,6)(3,7)(9,10,12,14)(11,13,16,15)(17,19,20,23)(18,21,22,24)(25,27)(26,32)(28,31)(29,39)(30,33)(34,36)(35,38)(37,40)(1,3)(2,4)(5,7)(6,8)(9,10)(11,13)(12,14)(15,16)(17,18)(19,21)(20,22)(23,24)(25,28,30,32)(26,33,31,27)(29,40,38,36)(34,35,37,39)(1,4)(2,3)(5,8)(6,7)(9,11)(10,13)(12,16)(14,15)(25,29,30,38)(26,34,31,37)(27,35,33,39)(28,36,32,40)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.