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)(11,20)(12,23)(13,24)(14,19)(15,16)(17,22)(18,21)(26,28)(31,33)(32,36)(38,39)(1,3,5,8)(2,6,4,7)(9,11)(10,14)(12,21)(13,22)(15,19)(16,20)(17,18)(23,24)(25,26,30,28)(27,31,35,33)(29,32,37,36)(34,38,40,39)(10,16)(11,19)(12,22)(18,24)(25,26,30,28)(27,33,35,31)(29,32,37,36)(34,39,40,38)(9,12,15,22)(10,17,16,23)(11,21,19,13)(14,18,20,24)(25,27,30,35)(26,31,28,33)(29,34,37,40)(32,38,36,39)(9,13,15,21)(10,18,16,24)(11,22,19,12)(14,17,20,23)(25,28,30,26)(27,33,35,31)(29,36,37,32)(34,39,40,38)(1,4,5,2)(3,7,8,6)(9,14,15,20)(10,19,16,11)(12,18,22,24)(13,23,21,17)(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.