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