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