  We present a detailed NMR study of the insulator to metal transition induced
by an applied pressure $p$ in the A15 phase of Cs$_{3}$C$_{60}$. We evidence
that the insulating antiferromagnetic (AF) and superconducting (SC) phases only
coexist in a narrow $p$ range. At fixed $p$, in the metallic state above the SC
transition $T_c$, the $^{133}$Cs and $^{13}$C NMR spin lattice relaxation data
are seemingly governed by a pseudogap like feature. We prove that this feature,
also seen in the $^{133}$Cs NMR shift data is rather a signature of the Mott
transition, which broadens and smears out progressively for increasing $(p,T)$.
The analysis of the variation of the quadrupole splitting $\nu _{Q}$ of the
$^{133}$Cs NMR spectrum precludes any cell symmetry change at the Mott
transition and only monitors a weak variation of lattice parameter. These
results open an opportunity to consider theoretically the Mott transition in a
multiorbital three dimensional system well beyond its critical point.
