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