To change the color for all of your items in a layer, follow the clicks below:
You can see the icons change from blue to green.

You could use this effectively by splitting your data into multiple layers when uploading, then indicating each layer as its own color (pizza places red, coffee shops brown, etc.)

If you have data in your dataset that can show various ranges, you can customize that quickly as well.

Here we change from "Uniform Style" to "Style by data column," then selecting the data we want to express.

I chose "YTD" to show how many books are checked out by location across the city.

Now select from preset color ranges for how the data will display. Library books are a positive story generally, so I'm choosing a green gradient.

The preset was 4 ranges. But I have a big dataset, and segmenting into percentiles of 10 is natural in our counting system, so I updated to 10. This also makes each range more precise than larger ranges.

Watch as the variety of colors changes in the image below -- you can learn more from the map with the updated ranges.

Want to make guides like this in seconds? Yes, it's really that fast.