How to properly plot a graph in networkx and export to json format.

hw_networkx.py

import numpy as np
import networkx as nx
import matplotlib.pyplot as plt

#embedding_coords = nx.spring_layout(G)
embedding_coords = nx.graphviz_layout(G)
#embedding_coords = nx.spectral_layout(G)
#embedding_coords = nx.random_layout(G)
# stored_coords = nx.get_node_aattributes(G, 'embedding')
# for k,v in stored_coords.iteritems():
#     stored_coords[k] = v[:2]
# embedding_coords = stored_coords # coordinates
labels = nx.get_node_attributes(G, 'name') # names for each node

# Set node colors with their betweeness centrality
btwns_c = nx.betweenness_centrality(G)
node_colors = btwns_c.values()

# Node size weighted by edges
edge_weights = nx.get_edge_attributes(G, 'weight')
node_weights = {}
for k,val in edge_weights.iteritems():
    u,v = k
    try: # this is a fast way to build dict
        node_weights[u] += val
    except KeyError:
        node_weights[u] = val; pass
for k in G.nodes():
    if k not in node_weights:
        node_weights[k] = 1;

# Adjusting the size so that some nodes are not going to take the whole plot
node_sizes = np.sqrt(node_weights.values())/15
#node_sizes = G.degree().values()

## Colors: http://matplotlib.org/api/colors_api.html
nx.draw_networkx_nodes(G, embedding_coords,
                       node_size = node_sizes,
                       node_color = node_colors,
                       cmap = plt.cm.Reds)
nx.draw_networkx_edges(G, embedding_coords, alpha = 0.2,
                       style = 'solid')
#                       edge_color = edge_weights.values())
# nx.draw_networkx_labels(G, embedding_coords, labels = labels, alpha = 1.0,
#                         font_size = 11, font_color = 'g', font_family = 'sans-serif')
plt.axis('off')
plt.title("<title of the graph plot>")
plt.show()
nx.write_dot(G, '<graphviz_saved_file_name>.dot')