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