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