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