\documentclass[class=minimal]{standalone}

\usepackage{tikz}
\usetikzlibrary{shapes.geometric}
\newcommand{\tiny}[1]{\scalebox{0.45}{#1}}

\begin{document}

\begin{tikzpicture}

\tikzstyle{title}=[text width=1.1cm, inner sep=0pt]
\tikzstyle{square}=[rectangle, draw, minimum width=0.5cm, minimum height=0.5cm, inner sep=0pt, fill opacity=0.5, text opacity=1]
\tikzstyle{op}=[ellipse, draw, inner sep=-1pt, minimum height=9pt, minimum width=12pt]
\tikzstyle{edge}=[->]
\tikzstyle{round}=[out=-90, in=90, looseness=0.85]

\node[title] at (-0.8, 2.2) {index};
\node[title] at (-0.8, 1.5) {input};
\foreach \i in {0,...,\numberInputs} {
  \pgfmathparse{\indices[\i]}\let\idx\pgfmathresult
  \pgfmathparse{\inputs[\i]}\let\in\pgfmathresult
  \pgfmathparse{\colors[\idx]}\let\co\pgfmathresult
  \node[square] (index\i) at (\i * 0.5, 2.2) {\idx};
  \node[square, fill=\co] (input\i) at (\i * 0.5, 1.5) {\in};
  \draw[edge] (index\i) -- (input\i);
}

\node[title] at (-0.8, 0.0) {out};
\foreach \i in {0,...,\numberOutputs} {
  \pgfmathparse{\outputs[\i]}\let\out\pgfmathresult
  \pgfmathparse{\colors[\i]}\let\co\pgfmathresult
  \def \x{(\numberInputs - \numberOutputs) * 0.25 + \i * 0.5}
  \node[op] (op\i) at ({\x}, 0.6) {\tiny{\operation}};
  \node[square, fill=\co] (output\i) at ({\x}, 0.0) {\out};
  \draw[edge] (op\i) -- (output\i);
}

\foreach \i in {0,...,\numberInputs} {
  \pgfmathparse{\indices[\i]}\let\idx\pgfmathresult
  \draw[edge] (input\i) to[round] (op\idx);
}

\end{tikzpicture}

\end{document}