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