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