Cfrgtkky

I would like to draw a regular 21 polygon, where the edges are labelled and have arrows in the middle using different colors. This is what I have done so far

using this code

    documentclass[margin=0pt]{standalone}

%---------------------------- Tikz Libraries ------------------------------%

usepackage{ifthen}

usepackage{tikz}

usetikzlibrary{shapes.geometric}

usetikzlibrary{decorations, decorations.markings} 

usetikzlibrary{arrows, arrows.meta}



%==========================  Middle & pointing arrows ==========================%

%-------------------------------------------------------------------------------%

% usage: draw[->-] or draw[->-=6pt red 1]

%-------------------------------------------------------------------------------%

tikzset{ ->-/.style args={#1 #2 #3}{

         decoration={markings,mark= at position 0.5 with {arrow{stealth}}, }, 

            postaction={decorate}, }, 

        ->-/.default= {0.5 6pt black }}





%==========================  Middle & pointing arrows ==========================%

%-------------------------------------------------------------------------------%

% usage: draw[-<-] path; or draw[-<-=6pt red 1] path;

%-------------------------------------------------------------------------------%

tikzset{ -<-/.style args={#1 #2 #3}{

        decoration={markings,mark= at position 0.5 with {arrow[>=stealth]{<}}, }, 

        postaction={decorate}, }, 

    -<-/.default= {0.5 6pt black }}





begin{document}



begin{tikzpicture}



node[fill=gray!10] (pol) [

  draw,

  minimum size=0.9textwidth,

  regular polygon, regular polygon sides=21,

  rotate=270,

  ]{};

foreach x/y/i in {1/2/1,5/6/2,9/10/3} %alpha's

  path[red,auto=right, ->-]

    (pol.corner x)--(pol.corner y)

      node[red,midway]{$alpha_{i}$};

foreach x/y/i in {3/4/1,7/8/2,11/12/3} %inverse alpha's

   path[red,auto=right, -<-]

     (pol.corner x)--(pol.corner y)

     node[red,midway]{$alpha_{i}$};

foreach x/y/i in {2/3/1,6/7/2,10/11/3} %beta's

  path[blue,auto=right, ->-]

    (pol.corner x)--(pol.corner y)

      node[blue,midway]{$beta_{i}$};

foreach x/y/i in {4/5/1,8/9/2,12/13/3} %inverse beta's

   path[blue,auto=right, -<-]

     (pol.corner x)--(pol.corner y)

     node[blue,midway]{$beta_{i}$};

foreach x/y/i in {13/14/1, 16/17/2,19/20/3} %xi's

  path[teal,auto=right,->-]

    (pol.corner x)--(pol.corner y)

      node[teal,midway]{$xi_ {i}$};

foreach x/y/i in {15/16/1,18/19/2,21/1/3} %inverse xi's

   path[teal,auto=right,-<-]

     (pol.corner x)--(pol.corner y)

     node[teal,midway]{$xi_{i}$};

foreach x/y/i in {14/15/1,17/18/2,20/21/3} %rho's

  path[violet,auto=right,->-]

    (pol.corner x)--(pol.corner y)

      node[violet,midway]{$rho_{i}$};

end{tikzpicture}

end{document}

Now, I would also like to color the edges of the polygon corresponding to the labels. But I am just able to color all edges in the same color. How can I do that?

like this:

for above image i made the following changes in mwe which you provide in question:

• delete option draw in polygon style definition


• all path in loops replace with draw