Let $A$ be a $(G, \chi)$-Hopf algebra with bijection antipode and let $M$ be
a $G$-graded $A$-bimodule. We prove that there exists an isomorphism
\mathrm{HH}^*_{\rm gr}(A, M)\cong{\rm Ext}^*_{A{-}{\rm gr}} (\K, {^{ad}(M)}),
where $\K$ is viewed as the trivial graded $A$-module via the counit of $A$,
$^{ad} M$ is the adjoint $A$-module associated to the graded $A$-bimodule $M$
and $\mathrm{HH}_{\rm gr}$ denotes the $G$-graded Hochschild cohomology. As an
application, we deduce that the cohomology of color Lie algebra $L$ is
isomorphic to the graded Hochschild cohomology of the universal enveloping
algebra $U(L)$, solving a question of M. Scheunert.