In Germany (aprox. 80 million spreakers) it is feminine, in Austria (aprox. 8.5 million speakers) it is neuter. So most native speakers say
die Cola
but in Austria it is
das Cola
Generally said: Softdrinks are female in Germany, but neuter in Austria.
Famous is »das Cola« from Red Bull. Red Bull is an Austrian Company, and beside the well known yellow energy drink, it also produces its own Cola. And this was its banner some times ago:

Addendum
Just to prevent misconceptions:
Neither »die Cola« nor »das Cola« are dialect variations. Both versions are standard German. But German has not one standard, it has tree standards:
- German German (spoken by 80M people)
- Austrian German (8.5M speakers)
- Swiss (Standard) German (5M speakers).
So German is a pluricentric language, like many other languages too (including English). The differences between the three variations go way beyond just the gender of softdrinks, but still are small enough so that a speaker of one variety will understand more than 99% of any other variety.
German German is kind of super-standard. This means: Almost all speakers of the two smaller varieties are bilingual: They actively use their own variety, but they also understand German German (and are able to speak it). This is why you will learn German German if you learn German as a foreign language. It allows you to communicate with everyone who speaks German. You just should know, that there are other variations too.
Standard means: Used to write laws and other official documents, printed in newspaper, spoken by news readers in TV and radio, and taught in schools. It is called "standard", because this languages are standardized: their orthography and grammar rules are written in books. Those rules are binding for students and officers, and they are recommendations for anybody else.
Dialect means: Only spoken language, not used for writing (exception: some song lyrics, poems and other kind of art), only used in private environments, never used for anything official. Dialects are not standardized: There is no set of rules, that is binding or recommended for anybody.