Diminished chord shapes are unique in the way that each note in the chord can be the root note, therefore each chord shape has four names.
For example, if the first chord on the right is played on the 2nd fret, the chord can be named either Gdim, Edim, Bbdim or C#dim. Although this is the case it is good to use diminished chords based upon one of the adjacent root positions.
Diminished
(Root Six)
Diminished
(Root Five)
Diminished
(Root Four)