\documentclass[a4paper]{article}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,positioning,matrix}
\begin{document}
\begin{tikzpicture}
\matrix (m) [matrix of math nodes,
row sep=3em, column sep=3em,
text height=1.5ex,
text depth=0.25ex]{
& \lambda\omega & & \lambda\Pi\omega \\
\lambda 2 & & \lambda\Pi 2 \\
& \lambda\underline{\omega} & & \lambda\Pi\underline{\omega} \\
\lambda{\to}& & \lambda\Pi \\
};
\path[-{Latex[length=2.5mm, width=1.5mm]}]
(m-1-2) edge (m-1-4)
(m-2-1) edge (m-2-3)
edge (m-1-2)
(m-3-2) edge (m-1-2)
edge (m-3-4)
(m-4-1) edge (m-2-1)
edge (m-3-2)
edge (m-4-3)
(m-3-4) edge (m-1-4)
(m-2-3) edge (m-1-4)
(m-4-3) edge (m-3-4)
edge (m-2-3);
\end{tikzpicture}
\end{document}
