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