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