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