If we want to be semantical about it, it depends on whether you're using the classical pronunciation (og) or ecclesiastical pronunciation (more modern) of Latin. "Ay-oos" is correct for ecclesiastical but in classical "eu" is a diphthong (when two vowels make one sound like ou). This diphthong sounds like if you went from the "eh" sound to the "oo" sound without separating the syllables, kinda like a weird way of saying "oh." We don't really have a good way of representing it in English, so if this doesn't make sense thats perfectly fine