  We present evidence of a drastic renormalization of the optical conductivity
of graphene on SrTiO$_3$ resulting in almost full transparency in the
ultraviolet region. These findings are attributed to resonant excitonic effects
further supported by \emph{ab initio} Bethe-Salpeter equation and density
functional theory calculations. The ($\pi$,$\pi$*)-orbitals of graphene and
Ti-3\textit{d} $t_{2g}$ orbitals of SrTiO$_3$ are strongly hybridized and the
interactions of electron-hole states residing in those orbitals play dominant
role in the graphene optical conductivity. These interactions are present much
below the optical band gap of bulk SrTiO$_3$. These results open a possibility
of manipulating interaction strengths in graphene via \textit {d}-orbitals
which could be crucial for optical applications.
