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)(11,13)(12,15)(14,16)(17,18,21,24)(19,22,20,23)(25,26,30,29)(27,33,35,31)(28,36,37,32)(34,38,40,39)(4,8)(6,7)(10,11)(12,16)(17,19,21,20)(18,22,24,23)(26,29)(28,37)(31,33)(34,40)(2,3)(6,7)(9,10,13,11)(12,15,16,14)(17,19,21,20)(18,22,24,23)(25,27,30,35)(26,31,29,33)(28,34,37,40)(32,38,36,39)(1,3,5,2)(4,7,8,6)(9,11,13,10)(12,15,16,14)(17,18)(19,22)(20,23)(21,24)(25,28,30,37)(26,32,29,36)(27,34,35,40)(31,38,33,39)(1,4,5,8)(2,6,3,7)(9,12)(10,14)(11,15)(13,16)(17,20,21,19)(18,23,24,22)(25,29,30,26)(27,31,35,33)(28,36,37,32)(34,38,40,39)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.