Personally, I say sen tore.
According to my classics professor ~20 years ago, we can’t know how “au” would’ve been pronounced in the greek.
He told us that ancient greek diphthong pronunciation is just made up. Apparently it’s much harder to reconstruct those sounds confidently, but that didn’t stop past classicists from claiming their reckonings as incontrovertible facts. Oxford and cambridge used to expell students for following the diphthong pronunciations of the other, but both are basically guesses.
Tauros in greek is bull, yeah. The minotaur was the Bull of Minos. It may link back to the pre-greek people of crete, known for bull-leaping.
The “ken” in “Kentauros” is thought to mean piercing, but why is a piercing bull a half man/horse? There’s no obvious explanation.
I love the idea of -tauros coming to mean a monstrous combination, like franken- in english. But if there were any evidence of that some very excited nerds would’ve told us, I’m sure.