You can create your own stylesheets by using StyleSheet class.
Just create an instance of the class and set the properties to the colors, etc.. you want. Once that is done, call the grid's ApplyStylesheet method with your stylesheet.
Dim styleSheet As New StyleSheet()
styleSheet.DataRows(0).BackColor = Color.Pink
styleSheet.DataRows(1).BackColor = Color.Green
' Don't forget to call the grid's ApplyStyleSheet
' method so that the new styles are reflected
' in the grid.
For more information, you can refer to theDataRowTemplate Stylestopic in the help file.