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