In the second picture there are branches. Locally you have 2 branches, master & develop. Both branches are resting at the same commit though. If you want to 'see branches' as in the first picture you can make a commit on develop, however the graph will still apear to be linear. You'll be able to merge develop into master at that point if you want.
If you want to see the graph diverge, try putting a commit on master as well. Then you will start to see something more like the first picture.
To get an idea of how git works with a visualization program like this, I suggest you do actions like I suggested above, and take a look at the graph at each intermediate step.
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