The way to approach this question if I were you would be to explore the parallels between Victor Frankenstein and the monster/creature that he creates and the relationship between the colonised and the European. Certainly, if we think of it this way, there is a lot about identity--a key post-colonial theme--that we could comment on. Consider the following point.
One crucial issue in colonialism is the way that Europeans went to places with the aim of "civilising" the natives, or teaching them how to be European and to reason and to read and write. Yet, having learnt such skills, the "natives" found that although they had been taught all of these skills, they could never "be" European because of their skin colour and physicial appearance. They had been educated like Europeans, thought like Europeans for the most part and fitted in to the European's lifestyle, but they were still not regarded as Europeans. In the same way, the creature has been created as human and with the capacity to reason, to love, to desire and to think, and yet, because of his physical appearance, he is at the same time denied companionship with human beings. Note what he says in Chapter Thirteen:
"I admired virtue and good feelings, and loved the gentle manners and amiable qualities of my cottagers, but I was shut out from intercourse with them, except through means which I obtained by stealth, when I was unseen and unknown, and which rather increased than satisfied the desire I had of becoming one among my fellows... What was I? The question again recurred, to be answered only with groans."
The rhetorical question "What was I?" points towards the importance of identity and how ambiguous this issue is for the creature. Just as colonial subjects had been "created" to resemble Europeans in their education, thought and values, so had the creature been created to be human. Yet both are fundamentally separate, in spite of these qualities, and were treated as such.