$index->setSettings([
  'renderingContent' => [
    'facetOrdering' => [
      'facets' => [
        'order' => [ 'gender', 'size', 'price' ]
      ],
      'values' => [
        'size' => [
          'order' => [ 'S', 'M', 'L', 'XL'],
          'sortRemainingBy => 'hidden'
        ],
      ]
    ]
  ]
]);

index.set_settings({
  renderingContent: {
    facetOrdering: {
      facets: {
        order: [ 'gender', 'size', 'price' ]
      },
      values: {
        size: {
          order: [ 'S', 'M', 'L', 'XL' ],
          sortRemainingBy: 'hidden'
        }
      }
    }
  }
})

index.set_settings({
  'renderingContent': {
    facetOrdering: {
      facets: {
        order: [ 'gender', 'size', 'price' ],
      },
      values: {
        size: {
          order: [ 'S','M', 'L', 'XL'],
          sortRemainingBy: 'hidden',
        },
      },
    },
  },
})