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