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