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