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