I am not able to understand what this plot depicts and what we mean by the relation between rankings.Let me add a few more things to make it a bit precise. This plot is generated by using plot_importance_rankings function available as part of randomForestExplainer package.
A sample code which generates this code is as
plot_importance_rankings(var_importance_frame)
where var_importance_frame contains important variables which we get as from
var_importance_frame <- measure_importance(rf_model)
Here rf_model is the trained random forest model. A sample example can be found at this link RandomForestExplainer - sample example