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