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