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