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