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