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