Drivers are ordered according to the order in which they started the stage. The points within each driver series correspond to the separate split times, in order. The y-axis is the time delta in seconds to the first driver onto the stage, which is why Ogier's times are flat with a delta of 0s at each timing point. The number labels are the in-class rank of the driver at each timing point.
So what can we learn, just from the chart? Firstly, Ogier seemed to lose it at the start. From the Red Bull TV (WRC Rally) coverage (and WRC/FIA footage on Youtube), it seems Ogier went for a little excursion at the start of the stage (stage 3), which accounts for his poor performance there, losing around about 40s compared to the other runners. The trends on Neuville's and Meeke's times are more or less flat, which shows they were approximately keeping time with each other, and with Ogier, across the other checkpoints. Latvala and Breen lost small amounts of time at each split, (the slight upward trend), Lefebvre more so, and Evans and Serderidis big time. Hanninen looked to be making time over the first part of the stage (the downward trend) before losing it on the last part.
Here's another view, rendered using seaborn.
I'll plot a code recipe at some point. Also, I think I'm pretty much committed to trying a Jupyter/python workflow for another data junkie data wrangling book on Leanpub, based around the WRC data...