my opinion here is that they are quite distinct visually, at least in my limited understanding.
cloak, though sleeveless, tends to cover the whole body or at least the upper body, usually with an opening or slit in the front, cutting the piece in half.
cape, as i see it, at most, covers the shoulders and the back. the torso or the front upper body is exposed, like superman.
if we implicate it, then it will be a bit hard to differentiate the two.