gridView1.OptionsView.GroupFooterShowMode = GroupFooterShowMode.VisibleAlways;
gridView1.CustomDrawRowFooter += (sender, e) =>
{
    e.Cache.FillRectangle(e.Cache.GetGradientBrush(e.Bounds, Color.Red, Color.Maroon, System.Drawing.Drawing2D.LinearGradientMode.Horizontal), e.Bounds);
    //Prevent default painting
    e.Handled = true;
};

GridGroupSummaryItem item = new GridGroupSummaryItem() {
    FieldName = "MPG Highway",
    SummaryType = DevExpress.Data.SummaryItemType.Sum,
    ShowInGroupColumnFooter = gridView1.Columns["MPG Highway"]
};
gridView1.GroupSummary.Add(item);
gridView1.CustomDrawRowFooterCell += (sender, e) =>
{
    e.Bounds.Inflate(-5, -5);
    e.Appearance.ForeColor = Color.Teal;
    e.Appearance.TextOptions.HAlignment = HorzAlignment.Center;
    e.Appearance.FontSizeDelta = 3;
    e.DefaultDraw();
    e.Cache.DrawRectangle(e.Cache.GetPen(Color.DarkOliveGreen, 5), e.Bounds);
    e.Handled = true;
};

Imports DevExpress.XtraGrid.Views.Base
Imports DevExpress.XtraGrid.Views.Grid

gridView1.OptionsView.GroupFooterShowMode = GroupFooterShowMode.VisibleAlways
AddHandler gridView1.CustomDrawRowFooter, Sub(sender, e)
    e.Cache.FillRectangle(e.Cache.GetGradientBrush(e.Bounds, Color.Red, Color.Maroon, System.Drawing.Drawing2D.LinearGradientMode.Horizontal), e.Bounds)
    'Prevent default painting
    e.Handled = True
End Sub

Dim item As New GridGroupSummaryItem() With {.FieldName = "MPG Highway", .SummaryType = DevExpress.Data.SummaryItemType.Sum, .ShowInGroupColumnFooter = gridView1.Columns("MPG Highway")}
gridView1.GroupSummary.Add(item)
AddHandler gridView1.CustomDrawRowFooterCell, Sub(sender, e)
    e.Bounds.Inflate(-5, -5)
    e.Appearance.ForeColor = Color.Teal
    e.Appearance.TextOptions.HAlignment = HorzAlignment.Center
    e.Appearance.FontSizeDelta = 3
    e.DefaultDraw()
    e.Cache.DrawRectangle(e.Cache.GetPen(Color.DarkOliveGreen, 5), e.Bounds)
    e.Handled = True
End Sub