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