In this work we present a theoretical analysis of plasmon nanoantennas for a diamond cluster containing a bright NV center. The results are obtained by the numerical simulations using the discrete dipole approximation. A gold shell around the diamond core is considered as antenna. It is shown that by varying the size of the nanodiamond core and the thickness of the gold shell the position of the plasmon resonance can be tuned to the emission of a NV center. A resonator shaped as a droplet-like metal cluster is proposed. It provides the selectivity of the radiation polarization that is required for applications in quantum informatics.