There are several ways to do this, and the simplest is to use the figure numbers. The code below makes two figures, #0 and #1, each with two lines. #0 has the points 1,2,3,4,5,6, and #2 has the points 10,20,30,40,50,60.
from pylab import *
figure(0)
plot([1,2,3])
figure(1)
plot([10, 20, 30])
figure(0)
plot([4, 5, 6])
figure(1)
plot([40, 50, 60])
show()