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