<｜begin▁of▁sentence｜>### Instruction:
As a Network Analysis Consultant working on a project for a popular fast-food chain with 127 locations, the task at hand involves utilizing the networkx library to create a graph representation of the restaurant locations linked in a binary tree structure. To enhance the project's visualization aspect, the challenge is to leverage the plot function provided by networkx with the Cairo backend to render the graph and securely store it as a PNG file for reporting purposes.
### Response:
from igraph import Graph, plot
import cairo

g = Graph.Tree(127, 2)

# Since AbstractCairoGraphDrawer is an abstract class, we will use
# the `plot` function which utilizes concrete implementations
# of the drawer based on the Cairo backend

# Create a Cairo surface to draw the graph
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 800, 600)

# Draw the graph on the surface
plot(g, target=surface)

# Save the surface to a PNG file
surface.write_to_png('tree_graph.png')
<|EOT|>
