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