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