Is it possible to change the default Green colour used for the wireframe/shaded view of the mesh in ABAQUS?

Yes its possible to change the colour Green. Click on the Common Plot option icon (the first one first row and the one on the left to the left of the viewport).

In the dialog box which opens choose the Color &/ style tab. There will be 3 lines of colours. The first one controls the colour for the wireframe of the mesh. Click on this colour and from the colour palette which appears choose the colour and click on OK.





The original view is as shown :
Click on OK and this should change the appearance.