@manooooh Could you try to replace
\foreach \X in {0,...,\totalnodes} {%
\layerCheckBox{}{myArrow\X}{on}\begin{tikzpicture}[baseline=-.82ex]%
\pgfmathsetmacro{\huenum}{\X*0.75*(1/\totalnodes)}%
\definecolor{mycolor}{hsb}{\huenum,1,1}\draw[-latex,mycolor,very thick] (0,0) -- (1,0);%
\end{tikzpicture}\quad
by
\foreach \X in {0,...,\totalnodes} {%
\layerCheckBox{}{myArrow\X}{on}\begin{tikzpicture}[baseline=-.82ex]%
\pgfmathsetmacro{\huenum}{\X*0.75*(1/\totalnodes)}%
\definecolor{mycolor}{hsb}{\huenum,1,1}\draw[-latex,mycolor,very thick] (0,0) -- (1,0);%