As the toggle switch is a component of my employer, I just use checkbox to replace in this example.

I think I can code for my question (as you can see my code shown as below) and I found why the toggle switch cannot be turned off by a button... It is because there is a bug in the toggle switch component of my employer and then I have eventually fixed the bug.

Anyway, let me show the code for this question (even it is not the answer for the fixing the bug that I really need):

import React from "react";
import "./styles.css";

export default function App() {
  const [isOn, setIsOn] = React.useState(
      { a: false , b: false, c: false }
    );

  const handleInputA = () => {
    setIsOn({ ...isOn, a: !isOn.a });
  }

  const handleInputB = (inputLabel) => {
    setIsOn({ ...isOn, b: !isOn.b });
  }

  const handleInputC = (inputLabel) => {
    setIsOn({ ...isOn, c: !isOn.c });
  }

  return (
    <>
      <input
        type="checkbox"
        checked={isOn.a}
        onClick={handleInputA}
      />a
      <br />
      <input
        type="checkbox"
        checked={isOn.b}
        onClick={handleInputB}
      />b
      <br />
      <input
        type="checkbox"
        checked={isOn.c}
        onClick={handleInputC}
      />c (The one that I want to do for this question.)
      <br />
      { isOn.c &&
        <button onClick={handleInputC}>Unselect C</button>
      }
    </>
  );
}

You may check to see the effect if you are interested: https://codesandbox.io/s/toggleswitch-tpkti

You can do something like this:

export default class App extends Component {

    state = {
        status: false,
        switchButton: "Off"
    }

    handleClick() {
        this.setState({
            status: !this.state.status,
            switchButton: !this.state.status ? 'ON' : 'OFF'
        })
    }


    render() {

        return (
            <button onClick={()=> this.handleClick()}>
                {this.state.switchButton}
            </button>
        );
    }
}

In react when you setState and want to use the previous value as the input you should do this:

setState(pre => !pre)

Here we get the current value by using pre in the useState function. This should work perfectly.