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