To fill the interior with some colour, you need a closed path, using e.g.
\draw[fill=pink] (0:\R)
\foreach \x/\l in
{120/$x^2z^2$,
240/$x^2y^2$,
360/$y^2z^2$
}
{-- node[auto,swap]{\l} (\x:\R)};
To decorate each segment of this path, we can use a technique described here.
\tikzset{
% style to apply some styles to each segment of a path
on each segment/.style={
decorate,
decoration={
show path construction,
moveto code={},
lineto code={
\path [#1]
(\tikzinputsegmentfirst) -- (\tikzinputsegmentlast);
},
curveto code={
\path [#1] (\tikzinputsegmentfirst)
.. controls
(\tikzinputsegmentsupporta) and (\tikzinputsegmentsupportb)
..
(\tikzinputsegmentlast);
},
closepath code={
\path [#1]
(\tikzinputsegmentfirst) -- (\tikzinputsegmentlast);
},
},
},
% style to add an arrow in the middle of a path
mid arrow/.style={postaction={decorate,decoration={
markings,
mark=at position .5 with {\arrow[#1]{stealth'}}
}}},
}
...
\draw[postaction={on each segment={mid arrow}},fill=pink] (0:\R)
... (continue like above)
When filling the interior, everything is covered that has been drawn there before, so we have to move the code for the arc and the central label downwards.
Regarding rotation, you have to decide whether the labels should stay horizontal (option rotate=90) or whether the baseline should be rotated as well, to be read with tilted head (\rotatebox of the whole tikzpicture).
\documentclass[border=1mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing,decorations.markings,arrows}
% From https://tex.stackexchange.com/a/69225
\tikzset{
% style to apply some styles to each segment of a path
on each segment/.style={
decorate,
decoration={
show path construction,
moveto code={},
lineto code={
\path [#1]
(\tikzinputsegmentfirst) -- (\tikzinputsegmentlast);
},
curveto code={
\path [#1] (\tikzinputsegmentfirst)
.. controls
(\tikzinputsegmentsupporta) and (\tikzinputsegmentsupportb)
..
(\tikzinputsegmentlast);
},
closepath code={
\path [#1]
(\tikzinputsegmentfirst) -- (\tikzinputsegmentlast);
},
},
},
% style to add an arrow in the middle of a path
mid arrow/.style={postaction={decorate,decoration={
markings,
mark=at position .5 with {\arrow[#1]{stealth'}}
}}},
}
\begin{document}
\begin{tikzpicture}[thick,rotate=90]
\newdimen\R
\R=2.7cm
\draw[postaction={on each segment={mid arrow}},fill=pink] (0:\R)
\foreach \x/\l in
{120/$x^2z^2$,
240/$x^2y^2$,
360/$y^2z^2$
}
{-- node[auto,swap]{\l} (\x:\R)};
\node {$x^2y^2z^2$};
\draw[-stealth'] (-150:{0.4*\R}) arc (-150:150:{0.4*\R});
\foreach \x/\l/\p in
{
120/{$x^2z$}/above,
240/{$xy^2$}/below,
360/{$yz^2$}/right
}
\node[inner sep=2pt,circle,draw,fill,label={\p:\l}] at (\x:\R) {};
\end{tikzpicture}
\end{document}