Shabbat/Yom Tov version 
On weekdays, this prayer ends with the words Shomer Amo Yisrael L'Ad. This is seen as appropriate for weekdays, when men go in and out in their weekday pursuits, and come in need of divine protection.
On Shabbat and Yom Tov, a longer version of this blessing is recited. The blessing is ended with the words Who spreads the shelter of peace upon us, upon all of his people Israel, and upon Jerusalem. The words And spread over us the shelter of Your peace that are normally recited earlier in the paragraph are repeated prior to the closing. This is a reflection of the peace that comes along with these special days, and that putting Jerusalem above everything else is important.
Hashkiveinu ADONAI eloheinu l’'shalom, v’'ha-amideinu malkeinu l’'chayim;
Ufros aleinu sukat sh’'lomecha,
V’'tak’'neinu b’'eitza tova mil’'fanecha,
V’'hoshieinu l’'ma-an sh’'mecha.
V’'hagein ba-adeinu, v’'haseir mei-aleinu, oyeiv, dever, v’'cherev, v’'ra-av, v’'yagon;
V’'haseir satan mil’'faneinu umei-achareinu,
Uv’'tzeil k’'nafecha tastireinu –-
Ki Eil shom’'reinu umatzileinu ata;
Ki Eil melech chanun v’'rachum ata.
Ushmor tzeiteinu uvo-einu –- l’'chayim ulshalom mei-ata v’'ad olam.
Ufros aleinu sukat shlomecha.
Baruch ata ADONAI, haporeis sukat shalom,
V’'al kol amo Yisrael v’'al Y’'rushalayim.
- There might be a slight difference depending on who the artist is.
- The Siddur companion By Paul H. Vishny, page 702
- The World of Prayer: Commentary and Translation of the Siddur By Elie Munk, page 13
- The Complete Artscroll Siddur, page 336