I think most people will immidiately query what else you've got in your list as what you arm your Talos with will likely be influenced by needs of the list as a whole.
Personally - and this is on the assumption that you've got sufficient anti-tank elsewhere - I would keep it with the stock twin-linked splinter cannon, stick a Liquifier gun on it and call it done. Decent range for whilst is floats across the board, something decent for when you get in close, and then the strength to rip open vehicles and heavy infantry as needed.
Again it depends how you're intending to use the Talos, what role you intend it to fill, how it'll be deploying most often, and what you have to support it.
There was another thread on Talos weapons previously that might have more useful advice.