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