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