http://blog.davidvassallo.me/2017/10/17/how-to-create-a-heatmap-graph-network-visualization/

graph_5.js

var cy = cytoscape({

    container: document.getElementById('graphNetwork'), // container to render in

    elements: cytoscape_elements, // list of graph elements


    style: [ // the stylesheet for the graph

     {

		selector: 'node',

        style: {

			'background-color': 'data(confidence)',

          	'label': 'data(label)',

           'text-opacity': 0.5,

           'font-size': "0.5em",

           'font-weight': "bold"

        }

      },

     {

		selector: 'node[backgroundColor = "src"]',

        style: {

           'background-color': '#58cdfc',

           'label': 'data(label)',

           'text-opacity': 0.5,

           'font-size': "1em"

        }

      },

      {

         selector: 'edge',

         style: {

            'width': 3,

            'line-color': '#ccc',

            'target-arrow-color': '#ccc',

            'target-arrow-shape': 'triangle'

         }

       }
 ]
});