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