I want to rotate several vectors in $\mathbb{R}^6$ by the same rotation matrix $M$. $M$ should be random but uniformly sample the rotation space. I know that the $6\times6$ length-preserving rotation matrix $M$ must fulfill $M^T=M^{-1}$ and for preservation of orientation we would additionally require $\text{det}(M)=1$ (Link). How can I calculate these random matrices? How to achieve random matrices with uniform random sampling?
I found this answer to calculate uniformly sampled random vectors but I also need the rotation matrix as I want to apply the same transformation several times.