How to plot data points and not centroids using sklearn k-means?
Scatter plots work well for 2 dimensional, continuous data. Like the toy examples you see everywhere.

But the data produced by tfidfvectorizer is high-dimensional and sparse.

It is to be expected that almost all points will have a 0 value in any two dimensions you plot. One does not simply plot test as 2d coordinates in a meaningful way. And regular k-means doesn't work that well either. The means just move close together, and all correspond to average stopword vectors - not very useful.