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