<｜begin▁of▁sentence｜>### Instruction:
As a work-from-home freelancer specializing in data visualization and network analysis, you have been assigned a project to create and store a specific graph using the Graph Atlas function in igraph. Your client has provided you with the index for the graph from the Graph Atlas and has requested that you display it with labels and save it as a GraphML file for further analysis. This task requires your expertise in using the igraph library and working remotely to complete this graph visualization and storage project.
### Response:
import igraph as ig

# Generate a graph from the Graph Atlas with index 6
atlas_graph = ig.Graph.Atlas(6)

# Optional: Plot the graph
ig.plot(atlas_graph, vertex_label=atlas_graph.vs.indices, bbox=(300, 300), margin=20)

# Save the graph to a file in GraphML format
atlas_graph.write_graphml('atlas_graph.graphml')
<|EOT|>
