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