why psi(r) graph of s orbital starts from maxima but not P,D,F.......

The hydrogen s orbitals correspond to l=0 and only allow ml=0. In this case, the solution for the angular wavefunction, Y0,0(θ,ϕ)is a constant. As a result, the Ψn,0,0(r,θ,ϕ)wavefunctions only depend on r and the s orbitals are all spherical in shape.Because Ψn,0,0depends only on r,
In case of other orbital it depends on the angle .
porbital-The angular wave functionY1,0(θ,ϕ)=cosθonly depends on θ.
Thus it does not starts from maxima