이런 느낌입니다

코드와 간단한 해설

import Foundation
import UIKit

class CellOnView{

    let cellOnView = UIView()

}

extension CellOnView{

    func createCellOnView(cellPointX:CGFloat,cellPointY:CGFloat,cellWidth:CGFloat,cellHeight:CGFloat,targetView:UIView){

        cellOnView.frame = CGRect(x: cellPointX, y: cellPointY, width: cellWidth, height:cellHeight)

        cellOnView.backgroundColor = .systemGreen

        targetView.addSubview(cellOnView)

    }
}

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {

        let selectCell = collectionView.cellForItem(at: indexPath)! as UIView

        cellOnView.createCellOnView(cellPointX: selectCell.bounds.minX, cellPointY: selectCell.bounds.minY, cellWidth: selectCell.frame.size.width, cellHeight: selectCell.frame.size.height, targetView: selectCell)

    }