\documentclass[tikz,border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{decorations}
\pgfdeclaredecoration{simple line}{initial}{%<------https://tex.stackexchange.com/a/216086/197451
\state{initial}[width=\pgfdecoratedpathlength-1sp]{\pgfmoveto{\pgfpointorigin}}
\state{final}{\pgflineto{\pgfpointorigin}}
}
\tikzset{
shift left/.style={decorate,decoration={simple line,raise=#1}},
shift right/.style={decorate,decoration={simple line,raise=-1*#1}},
}
\begin{document}
\begin{tikzpicture}[]
\tikzstyle{every node} = [circle, fill=red!30]
\node (a) at (0, 0) {A};
\node (b) at +(0: 5) {B};
\node (c) at +(60: 5) {C};
\foreach \from / \to in {a/b, b/c, c/a}
\draw [->] (\from) -- (\to);
\path[->,blue] (a) edge[shift left=4pt, shorten >=3em, shorten <= 3em] node[fill=none, above]{$e_2$}(b);
\path[->,orange] (b) edge[shift left=4pt, shorten >=3em, shorten <= 3em] node[fill=none, below]{$e_2$}(a);
\end{tikzpicture}
\end{document}