Total return variability in finance

I have been trying to produce a chart similar to the one depictedin this Vanguard article (rolling ten-year annualized return variability of total US stock market).

I don't quite have the same data series - I have total cumulative return for the S&P 500 from 1960. What steps can I follow to treat this single data series in Excel to arrive at something conceptually similar, expressed in percentage terms? I have tried to manipulate the data in various ways with moving averages/stdev/variance but the result looks totally different. Many thanks.