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