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