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