I would recommend the c# binding of SFML. I have used it in conjunction with Winforms before. You can just throw a control on your winform (I choose a Panel) to represent the area on your form you want to draw the graphics. You then pass in the control.Handle in when creating a RenderWindow.
Then you will override the OnPaint and OnPaintBackground events/functions of your control. In the OnPaint you will do all your SFML drawing. In the OnPaintBackground dont do anything (prevent it from painting background of the actual control). This will redraw when the control detects it needs to like something covering the window then uncovering it. If you need to continually redraw then you can do something like override the Idle function/event of the Form and call the Invalidate of the control from there to force a redraw. Or setup a Timer and call invalidate when the Timer fires.
How to use SFML is documented on their website on how to go from there. No real documentation on the embedded thing but on how to draw with SFML. http://www.sfml-dev.org/