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