This is not my code, I got it from a John Walkenbach book, but it works great...
Highlight your entire 7x5 grid and put this formula in the formula bar. You must hit Control-Shift-Enter to enter the formula. If the formula is not surrounded by these { }, you have not entered it correctly. You should format your grid as either d or dd (Custom Format). You can then add the name of the days (Mon, Tue, etc and the Month) as you see fit. The value in A1 should be something like 8/2015 for August...
=IF(MONTH(DATE(YEAR(A1),MONTH(A1),1))<>MONTH(DATE(YEAR(A1),MONTH(A1),1)-(WEEKDAY(DATE(YEAR(A1),MONTH(A1),1))-1)+{0;1;2;3;4;5}*7+{1,2,3,4,5,6,7}-1)," ",DATE(YEAR(A1),MONTH(A1),1)-(WEEKDAY(DATE(YEAR(A1),MONTH(A1),1))-1)+{0;1;2;3;4;5}*7+{1,2,3,4,5,6,7}-1)
HTH
igold