You can temporarily change the display option:
with pd.option_context('precision', 3):
print(df.head())
0 1 2 3 4
0 -0.462 -0.698 -2.030 0.766 -1.670
1 0.925 0.603 -1.062 1.026 -0.096
2 0.589 0.819 -1.040 -0.162 2.467
3 -1.169 0.637 -0.435 0.584 1.232
4 -0.704 -0.623 1.226 0.507 0.507
Or change it permanently:
pd.set_option('precision', 3)
A simple print(df.head().round(3))
would also work in this case. They will not change the DataFrame in place.