There doesn't seem to be. While in Modern Hebrew daftar (or diftar) means notebook, this is a borrowing from Arabic, where it also means now "book of accounts" (see here how that sense entered Hindi.) Arabic in turn borrowed the word from the Greek dipthera, meaning "leather, hide" - particularly for writing.
Talmudic Hebrew also borrowed from the Greek, and we find there the word diftera דפתרא - with the same meaning as the Greek. For example in Megillah 19a, we find: דיפתרא דמליח וקמיח ולא עפיץ "diftera is a skin prepared with salt and flour, but not with gallnut".
From the same Greek word we get the disease diptheria, as the Online Etymology Dictionary explains:
An unexpected derivative of dipthera is the English word "letter". Also from the OED:
coined 1857 in Fr. by physician Pierre Bretonneau from Gk. diphthera "hide, leather," of unknown origin; the disease so called for the tough membrane that forms in the throat.
c.1150, "graphic symbol, written character," from O.Fr. lettre, from L. littera (also litera) "letter of the alphabet," of uncertain origin, perhaps from Gk. diphthera "tablet," with change of d- to l- as in lachrymoseThis strange jump from Greek to Latin seems to have been aided by the mysterious Etruscans. This site explains:
Four words dealing with writing came into Latin by way of the Etruscan language, confirming the Etruscan transmission of the Greek alphabet to the Romans: elementum, whose earlier meaning was 'letter of the alphabet', litterae, 'writing' (originally derived from Greek diphthera, 'skin', a material on which people wrote); stylus, 'writing implement', and cera, 'wax' (for wax tablets on which to take notes).I started by saying that the word was probably not related to daf. Klein says that the etymology is unknown, but is "possibly related to Greek dephein, despein ( = to soften)." YourDictionary.com and Partridge's Etymological Dictionary agree.
On the other hand, Steinsaltz writes that the word may have been borrowed earlier from the Persain dipir, "scribe", which has the same Sumerian origin as daf.