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