Green’s Dictionary of Slang

(orig. US) a general excl. of annoyance, surprise etc.

1932		J.L. Kuethe ‘Johns Hopkins Jargon’ in AS VII:5 332: for crap’s sake—somewhat stronger than ‘for heaven’s sake.’.
1936		(con. 1920s) Dos Passos Big Money in USA (1966) 906: For craps’ sake, Charley, remember that the war’s over.
1962		P. Crump Burn, Killer, Burn! 100: Well, for crapsake.
1975		J. Wambaugh Choirboys (1976) 256: ‘Shit,’ said Sabrina. ‘Crapsake,’ said Tammy.