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