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