The graviton we find in string theory and in supergravity in a specific limit is the Rarita-Schwinger field. Specifically in order to get supergravity (let us forget string theory for now) we need to gauge the supersymmetry transformation parameters, i.e. $\epsilon_{\alpha} \to \epsilon_{\alpha}(x)$. Then the associated gauge field is the vector-spinor $\psi_{\alpha \, \mu}$ where $\alpha$ is the internal symmetry index and $\mu$ is the Lorentz index. Now gauging this parameter, which is a constant spinor, we get supergravity which is an interacting theory. The Rarita-Schwinger field is nothing more than the non-interacting or free limit. At this limit the various fields of the theory (which depend a lot on the supersymmetry(ies)) do not interact and we can consider them case by case. Then the vector-spinor field $\psi_{\alpha \, \mu}$ is the Rarita-Schwinger field which transforms in the $$ \Big( (1/2, 0) \oplus (0,1/2)\otimes (1/2,1/2) \Big) $$ of the Lorentz group. Just note that general supergravity theories restrict a lot the type of spinor $\psi_{\alpha \, \mu}$ is normally but for a free theory and for any dimension $d$ one can use a complex spinor with $2^{d/2}$ components. A nice review I found was this one where you will find much more (and accurate) info.