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