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