Whilst there have been plenty of attempts- for colour to denote Force Philosophy or seniority- it has proven impossible to say that sabre colour is down to anything other than preference.
Sabres are made of... well... hi-tech stuff. We know they have crystals that act as batteries (some people think the crystals are for focussing but thay seems doubtful).
Canonical stuff on it is non-existant; the ROTJ radio version has some semi-canon comment on it.
My thoughts...
The crystal is for focasing a light into a laser (like a real laser).
The technical part in the sabre handle is the bit that controls the blade length/intensity.
The colour of the blade comes from colour of the crystal which is down to the preference of the maker.
I seem to remember Gantoris made a multi-crystal sabre that could change colour.