You don't need the Panel at all.
Create your own DGV class by inheriting from it, then override the OnPaint method with something like:
Public Class MyDGV
Protected Overrides Sub OnPaint(e As System.Windows.Forms.PaintEventArgs)
Private Sub MyLinePaintingCode()
Dim g As Graphics = Me.CreateGraphics
Then you don
Your custom DGV will show up in the Toolbox. Use that one instead of the default DGV control and your done.