Please understand that we are not expected to explain the whole graph in 40 secs. It is highly impossible. They check whether our speech is naturally flowing and are we able to convey the information effectively. Here slow and steady wins the race. We should be clearly speaking with optimal pace. Never rush to tell all the information. This might penalize you on pronunciation, meaning computer might not be able to correctly capture all your words.
-The graph shows/displays the number of ITunes songs bought …,
-In this graph, we can see the number of ITunes songs purchased …,
-The photo/image shows a (scene, buildings, place) from a distance
-The information indicates…, From the chart/graph…, We can conclude that…
** You should include an introduction, a main body and a conclusion in your description
**If you lack points to speak, speaking something like, “It is really interesting to know this information” or something of this sort.”