Grouped Force Layout

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.links line {
  stroke: #999;
  stroke-opacity: 0.6;
}

.nodes circle {
  stroke: #fff;
  stroke-width: 1.5px;
}

path {
	opacity: 0.4;
	stroke-width: 0px;
    pointer-events: none;

}

</style>
<svg width="960" height="600"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height");

var color = d3.scaleOrdinal(d3.schemeCategory20);

var voronoi = d3.voronoi()
    .x(function(d) { return d.x; })
    .y(function(d) { return d.y; })
    .extent([[-1, -1], [width + 1, height + 1]]);

d3.json("data.json", function(error, graph) {
  if (error) throw error;

var link = svg.append("g")
      .attr("class", "links")
    .selectAll("line")
    .data(graph.links)
    .enter().append("line")
      .attr("stroke-width", function(d) { return Math.sqrt(d.value); });

var node = svg.append("g")
      .attr("class", "nodes")
    .selectAll("circle")
    .data(graph.nodes)
    .enter().append("circle")
      .attr("r", 5)
      .attr("fill", function(d) { return color(d.group); })
      .call(d3.drag()
          .on("start", dragstarted)
          .on("drag", dragged)
          .on("end", dragended));

node.append("title")
      .text(function(d) { return d.id; });

simulation
      .nodes(graph.nodes)
      .on("tick", ticked);

simulation.force("link")
      .links(graph.links);
	  
	  
  // append voronoi  
  var cells = svg.selectAll()
  .data(simulation.nodes())
  .enter().append("g")
  .attr("fill",function(d) { return color(d.group); })
  .attr("class",function(d) { return d.group })

var cell = cells.append("path") 
	.data(voronoi.polygons(simulation.nodes()))

var r = Math.sqrt(dx*dx+dy*dy)
			
		if (r>minDistance) {
			d.x = x * 0.9 + cx * 0.1;
			d.y = y * 0.9 + cy * 0.1;
		}
	})

// update voronoi:
    cell = cell.data(voronoi.polygons(simulation.nodes())).attr("d", renderCell);
  
    // update links:
    link
        .attr("x1", function(d) { return d.source.x; })
        .attr("y1", function(d) { return d.source.y; })
        .attr("x2", function(d) { return d.target.x; })
        .attr("y2", function(d) { return d.target.y; });

// update nodes:
    node
        .attr("cx", function(d) { return d.x; })
        .attr("cy", function(d) { return d.y; });
  }

});

function dragstarted(d) {
  if (!d3.event.active) simulation.alphaTarget(0.3).restart();
  d.fx = d.x;
  d.fy = d.y;
}

function dragged(d) {
  d.fx = d3.event.x;
  d.fy = d3.event.y;
}

function dragended(d) {
  if (!d3.event.active) simulation.alphaTarget(0);
  d.fx = null;
  d.fy = null;
}

function renderCell(d) {
  return d == null ? null : "M" + d.join("L") + "Z";
}

</script>

https://d3js.org/d3.v4.min.js