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