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