As per this example:
import numpy as np
import matplotlib.pyplot as plt
N = 50
x = np.random.rand(N)
y = np.random.rand(N)
plt.scatter(x, y)
plt.show()
will produce:
To unpack your data from pairs into lists use zip:
x, y = zip(*li)
So, the one-liner:
plt.scatter(*zip(*li))