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