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