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