Animate molecular vibrations as multiple xyz coordinate files
If I remember correctly, frequency data are in the stdout clusterfuck usually named log file, as well as in the (formatted) checkpoint files. There shouldn't be any need to prepare a cube file for this.

If GaussView is not available, GM's comment has the answer: Avogadro can visualize vibrations and I'm sure I've done this. Unfortunately, I don't have an output file at hand here.