A new Lax pair for the sixth Painleve equation associated with $hat{mathfrak{so}}(8)$

A new Lax pair for the sixth Painleve equation $P_{VI}$ is constructed in the framework of the loop algebra $mathfrak{so}(8)[z,z^{-1}]$. The whole affine Weyl group symmetry of $P_{VI}$ is interpreted as gauge transformations of the corresponding linear problem.