Vizmapper is available in Cytoscape 2.x versions. In Cytoscape 3.x use the "Style" tab in the Control Panel (to the left of the network) to customize node and edges of the network.

If you are using Cytoscape 3.2.1, then after importing your network,

1. On the menu bar, click, File->Import->Table->File
2. Select the node attributes file that you have and click "Open"
3. A dialog box called "Import columns from table" opens. Check other options on that dialog box and simply select the network you want to append the node attributes to, in the "Network Collection" drop down menu. Keep the "Import data as: Node columns" option as it is and click "Ok".
4. Done ! Now you can apply all the styles to nodes and edges as mentioned above using the "Style" tab.