\begin{tikzpicture}[x=1.5cm,y=1.0cm]
    % Nodes
    \node[latent] (x) {$x_t$} ; %
    \node[latent, left=of x] (x1) {$x_{t-1}$} ; %
    \node[latent, above=of x1] (x2) {$x_{t-2}$} ; %
    %
    \node[latent, left=of x1] (x3) {$x_{t-3}$} ; %
    \node[obs, above=of x3] (x4) {$x_{t-4}$} ; %
    % 
    \node[latent, left=of x3] (x5) {$x_{t-5}$} ; %
    \node[latent, above=of x5] (x6) {$x_{t-6}$} ; %
    
    \node[draw=none] (q) [left=of x5] { }; %
    \node[draw=none] (r) [left=of x6] { }; %
    \node[draw=none] (i) [above=of x4] { }; %

    % % Edges
    \edge {x1} {x}  ; %
    \edge {x2} {x}  ; %
    \edge {x2} {x1} ; %
    \edge {x3} {x1} ; %
    \edge {x3} {x2} ; %
    \edge {x4} {x2} ; %
    \edge {x4} {x3} ; %
    \edge {x5} {x3} ; %
    \edge[red] {x5} {x4} ; %
    \edge[red] {x6} {x4} ; %
    \edge {x6} {x5} ; %
    
    \edge[dashed]{q}{x5}
    \edge[dashed]{r}{x6}
    \edge[dotted]{i}{x4}
    \path (i) -- (x4) node [midway,right](TextNode){$do(x_{t-4} = x*_{t-4})$};
  
    
    % % Label edges by redrawing invisible lines with regular tikz commands
    % \path (x) -- (y) node [midway,above](TextNode){$\beta$};
    % \path (z) -- (x) node [midway,left](TextNode){$M$};
    % \path (z) -- (eps) node [midway,above](TextNode){$c$};
\end{tikzpicture}