Interference graphs are basically required in networks with multiple transceivers(tx/rx). They map which network communication can occur in parallel without collision. They help reduce collisions in large networks. They are especially useful in WiFi network, where multiple clients can transmit simultaneously and might be mutually invisible to each other. They are also particularly useful in adhoc mesh networks to improve reliability. There are active and passive algorithms for creating these graphs. Please revert back with the type of algorithm and the type of network you are working with for a detailed analysis