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