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