Go read more
Lovecraft. Or simply consider the distinction between feel and appearence.
Of course the Alien doesn't look like Cthulhu.
The first Alien has a great Lovecraft vibe into it - mainly in the part involving the Derelict. Theme of the unknown, of the mysterious, of the immensity that is in the universe and that we don't know a comma of. The Aliens are unknown and mysterious, we don't know where they are from, we don't know why they were in that ship, we don't know their purpose. They can be for the Jockeys what the Shoggoths are for the Ancient Ones, for example.
That is how I see it at least, if you don't share this, fine as well.
