When viewing the map on a listing (Agent Full display, for instance), there are a couple of icons at the top of the map:
If you hold your mouse over each one for a couple of seconds, a little box will open and tell you what it is:
Click the Layers icon.
Flood Zones is in the middle of the Boundaries section of the list:
The color-coded flood zones will now appear on your map:
If you do not see the flood zones, you are probably zoomed too far out on the map. Click the plus sign in the upper right corner to zoom in until the flood zones appear.