Taxes paid by your employer are indeed paid by you. If your salary is X and the company is paying Y worth of payroll tax, then they're really paying X+Y for your services, which would all be salary going to you if not for the payroll tax.
But the value Y could also be put towards hiring somebody else to do an additional job, giving somebody else a pay rise, or giving money to the shareholders.
As I pointed out elsewhere, "X+Y... would all be salary going to you if not for the payroll tax" makes the assumption that companies are currently paying 100% of what they could possibly be willing to pay for that employee's labor. Given the profitability of California's companies, I suspect there's some surplus there. And a surplus suggests that the value of the labor is being driven moreso by what price will attract sufficient employees, which would only change due to 2nd or 3rd order effects by the elimination of payroll taxes (via competitors willing to pay more for a finite pool of top laborers popping up).