Adding shortcode attributes
You can add your custom attributes to be handled by the ACF fields. For this you will need to add the attribute to the field-type that handles the output. When that's done, you can add or replace the output-filters to use that attributes value.
Adding the attribute to the field-type
Add the attribute my merging it with the existing attributes that are used by a specific field-type:
Using the attribute
When the field-type has the custom attributes applied, it will be able to pass those attributes to the output-filters. You can now write your callbacks to use those attributes.
The following example will add a colored border around a google_map field-type, whenever a color-attribute has been provided and is set.