In the case of $n = 2$, a hyperbolic rotation matrix by an arbitrary angle looks like:
$\begin{bmatrix} \cosh(\theta) & \sinh(\theta)\\ \sinh(\theta) & \cosh(\theta) \end{bmatrix}$
$\forall \theta \in \mathbb{R}^{1}$
These are Hermitian matrices with real entries. So is there a specific name/symbol for the n-dimensional real Hermitian matrix group? These are the hyperbolic equivalent of the SO(n) groups.
I've seen the matrices you've written referred to as "hyperbolic rotations", and they/related matrices appear in discussions of the Lorentz group(s), like the Wikipedia entry for "rapidity".
In higher dimensions, I am not sure if the Lorentz group is what you're looking for, though.