\begin{tikzpicture}[x=1cm,y=1cm]
  \coordinate (r) at (0,0);
  \coordinate (u1) at (2,1);
  \coordinate (u2) at (2,0);
  \coordinate (u3) at (2,-1);
  \foreach \j in {1,2,3}{
    \draw[fold edge] (r)--(u\j)
      node[midway,above,sloped,font=\small] {$e_{\j}$};
    \node[part B] at (u\j) {};
    \node[right=3pt,font=\small] at (u\j) {$u_{\j}$};
  }
  \node[part A] at (r) {};
  \node[left=3pt,font=\small] at (r) {$r$};
  \node[diagram label] at (1,2.8) {$H=K_{1,3}$};
  \node[font=\small,text=foldblue] at (1,-1.85)
    {$t_{12}:u_2\mapsto u_1$};
  \node[font=\small,text=foldorange] at (1,-2.35)
    {$t_{13}:u_3\mapsto u_1$};

  \tikzset{
    pair state/.style={ellipse,draw=foldgray,line width=.7pt,
      fill=white,inner xsep=5pt,inner ysep=5pt,font=\small},
    pair blue/.style={diagram arrow,draw=foldblue},
    pair orange/.style={diagram arrow,draw=foldorange},
  }
  \node[pair state] (p23) at (5,0) {$\{e_2,e_3\}$};
  \node[pair state] (p13) at (7.65,1) {$\{e_1,e_3\}$};
  \node[pair state] (p12) at (7.65,-1) {$\{e_1,e_2\}$};
  \node[pair state,draw=foldgreen,fill=foldgreen!6] (p11)
    at (10.4,0) {$\{e_1,e_1\}$};
  \node[diagram label] at (7.65,2.8) {Edge-pair states};
  \draw[pair blue] (p23)--(p13)
    node[midway,above,sloped,font=\small,text=foldblue] {$t_{12}$};
  \draw[pair orange] (p23)--(p12)
    node[midway,below,sloped,font=\small,text=foldorange] {$t_{13}$};
  \draw[pair orange] (p13)--(p11)
    node[midway,above,sloped,font=\small,text=foldorange] {$t_{13}$};
  \draw[pair blue] (p12)--(p11)
    node[midway,below,sloped,font=\small,text=foldblue] {$t_{12}$};
  \draw[pair blue] (p13) to[loop above]
    node[font=\small,text=foldblue] {$t_{12}$} (p13);
  \draw[pair orange] (p12) to[loop below]
    node[font=\small,text=foldorange] {$t_{13}$} (p12);
  \node[font=\small,text=foldgreen] at (10.4,-1.05) {merged};
\end{tikzpicture}