This can be done by implementing a custom checkbox.

To do this, navigate to **\Views\FormBuilder\FieldTemplates** in your sitecore solution.

Duplicate the file **Checkbox.cshtml** and update the file to look like below:

    @using Sitecore.ExperienceForms.Mvc.Html
    @model Sitecore.ExperienceForms.Mvc.Models.Fields.CheckBoxViewModel
    
    <label class="customCheckbox @Model.LabelCssClassSettings.CssClass">
        <input type="checkbox" id="@Html.IdFor(m => Model.Value)" name="@Html.NameFor(m => Model.Value)" class="@Model.CssClassSettings.CssClass"@if (Model.Value) {<text> checked="checked"</text>} value="true" data-sc-tracking="@Model.IsTrackingEnabled" data-sc-field-name="@Model.Name" data-sc-field-key="@Model.ConditionSettings.FieldKey" @Html.GenerateUnobtrusiveValidationAttributes(m => Model.Value)/>@Html.DisplayTextFor(t => Model.Title)
        <input type="hidden" name="@Html.NameFor(m => Model.Value)" value="false"/>
    </label>
    @Html.ValidationMessageFor(m => Model.Value)

Note the single addition to the file to include adding the **customCheckbox** class to the label. 

Create a new javascript file called **customCheckbox.js**

    $(".customCheckbox input[type='checkbox']").click(function(){
    	var fieldName = $(this).attr("data-sc-field-name");
    	if(fieldName=="All"){
      		if($(this).hasClass('checked'))
    		{
    			$(this).removeClass("checked");
    			$(".customCheckbox").each(function() {
    				$(this).children("input[type='hidden']").first().val("false");
    				$(this).children("input[type='checkbox']").prop( "checked", false )
    			});
    		}
    		else
    		{
    			$(this).addClass("checked");
    			$(".customCheckbox").each(function() {
    				$(this).children("input[type='hidden']").first().val("true");
    				$(this).children("input[type='checkbox']").prop( "checked", true )
    			});
    		}
    	}
    });

Note also the line `if(fieldName=="All"){` this checks if the field name of the checkbox that has been clicked is called 'All'. **You need to ensure the field name of your checkbox is named as such**.

You also need to add the JS file to your solution. Do do this, place the new file in this location:
<siteroot>/sitecore modules/Web/ExperienceForms/scripts

Then go to your form in the content editor and add it in the scripts field:
[![Custom Checkbox form js][1]][1]

To start using this custom checkbox in your sitecore form you need to overwrite the existing Checkbox to use new view (not recommended - but good for quick test purposes locally). Or create a new field by duplicating the existing and adding your new view.
[![Custom Check box][2]][2]

**Update:** I have updated this answer to use an external javascript file and more generic selector approach. It previously had the more specific js being output inline on each checkbox render.

  [1]: https://i.sstatic.net/7dLT1.png
  [2]: https://i.sstatic.net/jlJmF.png