A way to Change a Utility Meter's History Colors?

Configuration Frontend
4

Or use a custom history-explorer card (very customizable):
image

type: vertical-stack
title: state colors
cards:
  - type: entities
    entities:
      - entity: input_select.testing_value
  - type: custom:history-explorer-card
    defaultTimeRange: 5m
    stateColors:
      input_select.testing_value.one: red
      input_select.testing_value.two: orange
      input_select.testing_value.three: yellow
      input_select.testing_value.four: green
      input_select.testing_value.five: lightblue
      input_select.testing_value.six: blue
      input_select.testing_value.seven: violet
    graphs:
      - type: timeline
        entities:
          - entity: input_select.testing_value

Ofc it is about a particular card, not a History page.