You can change Pen and Brush property in inspector (see it in Editor demo),but also you can do it by code.

Code example:

procedure TMainFrm.Button1Click(Sender: TObject); 
var 
  mMyShape:TMyShape; 
begin 
  mMyShape:=MyCAD1.GetSelectedShape; 
  IF mMyShape <> nil then  
  begin 
  mMyShape.Pen.Color:=clRed; 
  mMyShape.Brush.Color:=clGreen; 
  mMyShape.Brush.Style:=bsSolid; 
  end; 
end;