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