A force-directed network graph displays character relationships from Les Misérables, with nodes representing characters and links showing their connections. The visualization uses d3.forceSimulation with link, charge, and center forces to position the nodes, while the links are rendered as SVG lines and nodes as circles. Users can drag any node to interact with the layout, as the code enables d3.drag on the circles with start, drag, and end handlers that fix and release the dragged node's position during the simulation.