\documentclass{article}
\usepackage{com.braju.graphicalmodels}
\usepackage{amsmath}
% \special{papersize=40mm,80mm}
% \setlength{\pdfpagewidth}{40mm}
% \setlength{\pdfpageheight}{80mm}
% \usepackage[vcentering,dvips]{geometry}
% \geometry{papersize={80mm,120mm},total={80mm,120mm},margin=0mm}



\catcode`\@=11%

\pagestyle{empty}

\begin{document}
\TeXtoEPS

\LARGE
\psset{unit=10mm,arrowscale=1.5,linewidth=1.5pt}

\begin{pspicture}(0,0)(8,8)
  \SpecialCoor

  % S
  \rput(1,1){\rnode{s_1}{$s_1$}}
  \rput(3,1){\rnode{s_2}{$s_2$}}
  \rput(2,3){\rnode{s}{$s$}}  

  % U
  \rput(5,1){\rnode{u_1}{$u_1$}}
  \rput(7,1){\rnode{u_2}{$u_2$}}
  \rput(6,3){\rnode{u}{$u$}}
  
  % T
  \rput(4,5){\rnode{t}{$t$}}
  \rput(6,7){\rnode{root}{$root$}}
    
  % bag
  \psset{linecolor=red}
  \pspolygon(0.2,0.5)(3.8,0.5)(2,4)
  \pspolygon(4.2,0.5)(7.8,0.5)(6,4)
  \pspolygon(3.8,4.5)(7.3,7.5)(3,7.5)
  
  % V
  \psset{linecolor=blue}
  \pscurve(2.8,8.5)(3.1,3.7)(4.3,0)
  \rput(3.3,8.1){\blue $\boldsymbol{v}_{st}^{+}$}
  
  \psset{arrows=-,nodesep=5pt,linecolor=black}
  \ncline{s}{s_1}
  \ncline{s}{s_2}
  \ncline{u}{u_1}
  \ncline{u}{u_2}
  \ncline{t}{u}
  \ncline{t}{s}
  \ncline{root}{t}
  
  \psset{arrows=->,nodesep=8pt,arrowsize=8pt,linewidth=3pt,linecolor=green}
  \ncline[offset=-8pt]{root}{t}
  \ncline[offset=8pt]{u}{t}
  \ncline[offset=-8pt]{t}{s}
  
\end{pspicture}

\endTeXtoEPS
\end{document}