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)(21,24,22,23)(25,26,31,36)(27,32,37,39)(28,34,29,33)(30,35,40,38)(1,2)(3,6)(4,5)(7,8)(9,11,16,14)(10,15,20,19)(12,21,13,22)(17,24,18,23)(25,27,31,37)(26,32,36,39)(28,38,29,35)(30,33,40,34)(2,5)(6,8)(9,12,16,13)(10,17,20,18)(11,21,14,22)(15,24,19,23)(25,28,31,29)(26,33,36,34)(27,35,37,38)(30,39,40,32)(3,7)(6,8)(9,13,16,12)(10,18,20,17)(11,21,14,22)(15,24,19,23)(25,27)(26,32)(28,35)(29,38)(30,33)(31,37)(34,40)(36,39)(1,3,4,7)(2,6,5,8)(9,14,16,11)(10,19,20,15)(12,22,13,21)(17,23,18,24)(25,29,31,28)(26,34,36,33)(27,35,37,38)(30,39,40,32)(1,2)(3,6)(4,5)(7,8)(9,15,16,19)(10,11,20,14)(12,23,13,24)(17,22,18,21)(25,30)(26,35)(27,33)(28,32)(29,39)(31,40)(34,37)(36,38)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.