Education is a noun, while educational is an adjective. In English however nouns can be used as adjectives. For this reason, both forms - educational company and education company - are possible and correct. They may have different connotations though. To my ears, an educational company would be a company that educates, which does not make a lot of sense. An education company would be a company that operates in the field of education, which sounds better to me. Native speakers may have a more accurate opinion.

You can see more about nouns used as adjectives at:

Happy 2014 for all of you!!

Ricardo - EMB