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