Yeah, I think Cyrenaica (that is, the Cyrenaican coast) is perhaps possible, but first of all, why would the Greeks want it, or any other colony? Greek foreign policy between 1844-1923 was a battle between the Megali Idea (the idea of liberating lands with substantial Greek populations, focusing on the then-Ottoman Empire-held areas) and some kind of 'Opportunistic isolationism' or outright non-intervention advocated by the so-called Eastern Party (Ion Dragoumis). Not only that, being a colonial power would go directly against the ideas that guided the Greek Revolution, its Declaration of Independence, and Constitutional principles. Mind you, even in arguable the best of times Greece had until the contemporary era (mid-70s until mid-2000s), that is 1910-1914, nationalism anti-colonialism was in the rise across the world. It would be a nightmare trying to even get small bits of land far from the mainland, let alone keeping them. Most importantly, zero people would be interested in such a project when you had rich and/or Greek-majority areas under foreign control.
Essentially, you need to go before the French Revolution, or even the Enlightenment, create something equivalent to a Greek-speaking state, probably with a different sense of idendity and founding principles, perhaps resembling more 12th/13th century Byzantium in terms of occupied land and encompassing populations. Then have it obtain some small outposts, presumably with view to facilitating trade with Egypt and/or India.
