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