Install the X11 server.
# apt-get install xorg
Install the gnome-desktop task
# tasksel install gnome-desktop --new-install(
# tasksel -t install gnome-desktop debconf-apt-progress -- apt-get -q -y -o APT::Install-Recommends=true -o APT::Get::AutomaticRemove=true install task-gnome-desktop)
Start X11
# startx