When it comes to the different colors for different bars, this is something that we don't plan to support in Lens/Visualize, but you could use Vega, which is more complicated to write. However, maybe there are some workarounds in Lens that could serve you. Color on the bar chart can be set by breakdown dimension. If you know the values of the field that are different for each graph, you can set up the exact filters to achieve it, below is the example configuration.
Tell me more about your usecase and I'll try to figure it out.
For a string field:
For a timefield with an interval of 1d:
