<｜begin▁of▁sentence｜>### Instruction:
As a Substance Abuse Counselor, you may need to work with different individuals or groups in a variety of settings to support them in achieving recovery from substance abuse, addiction, or dependency. Just as you tailor your counseling and interventions to meet the specific needs of your clients, when using the igraph library to draw a graph onto an image surface, you may need to define a custom bounding box for the DescartesCoordinateSystem within the image surface. This will allow you to margin the graph layout properly on the image, ensuring that it is displayed in a way that best suits the requirements of your project. You can do this using igraph's Cairo drawing backend.
### Response:
import igraph as ig
import cairo

# Read the graph
graph = ig.read('network.gml')

# Set up Cairo surface for drawing
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, 800, 600)
ctx = cairo.Context(surface)

# Create a Descartes coordinate system
coords = ig.drawing.cairo.DescartesCoordinateSystem(ctx)

# Set the bounding box for the coordination system
coords.bbox = (100, 100, 700, 500)

# Create a plot object with the given coordinate system
plot = ig.Plot(surface, coords, background='white')
plot.add(graph)

# Redraw and save the plot
plot.redraw()
surface.write_to_png('graph_layout.png')
<|EOT|>
