Youmightsayhave a goodweekendoryoumightsayseeyouonMonday.
良い週末を、と言うかもしれないし、月曜日に会おう、と言うかもしれない。
SoifyourworkweekgoesfromMondaytoFridayandit's around 4.30 orfive o'clockonFridayandyou'reabouttogohome, youwoulddefinitelysayhave a goodweekendorseeyouonMonday.