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