If you've taken physics, treat them as vectors, and find the sum of the vectors.
If not, do it qualitatively. The up arrow and the down arrow cancel each other out. There are two horizontal right arrows. There are two diagonal left arrows. The slope of the two diagonal arrows are equal and opposite, thus the vertical component of those arrows cancel. The horizontal component of those arrows is additive, so there are also two 'arrows' pointing to the left.
So the only net arrows to worry about are the two right arrows and the two horizontal components of the left arrows. The sum of the horizontal components of the left arrows are smaller than the right arrows, so the left arrows cancel some of the right arrows, but not all.
Small dipole moment with the + on the left and the arrow pointing right.