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