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