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