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)(11,18)(12,16)(13,22)(14,17)(15,20)(19,24)(21,23)(25,26,31,28,30,34,35,38)(27,32,29,33,36,37,39,40)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,21)(13,19)(14,20)(16,24)(17,18)(22,23)(25,27)(26,32)(28,33)(29,31)(30,36)(34,37)(35,39)(38,40) involution — undirected(2,6)(3,7)(25,28,31,34,30,38,35,26)(27,33,29,37,36,40,39,32)(2,6)(5,8)(9,12,14,13)(10,16,17,22)(11,19,20,21)(15,23,18,24)(25,29)(26,33)(27,35)(28,37)(30,39)(31,36)(32,38)(34,40)(9,13,14,12)(10,16,17,22)(11,19,20,21)(15,24,18,23)(27,36)(29,39)(32,37)(33,40)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.