Hmm that's weird, I'm actually seeing the same on my end, not sure why the option isn't showing up and I agree it should. You can still add it into aes() regardless, here is an example:
# Making a 2 row example dataframe to use for a simple ggplot
example_data <- data.frame(x=c(1,2), y=c(2,3), color_column=c('text1', 'text2'))
# See below on where to place `colour=`
ggplot(example_data, aes(x = x, y = y, colour = color_column)) + geom_point(aes())
And you should see a chart that looks like this:
Try to see where I placed colour=c and try to replicate that for your data.
You can also wrap it in geom_point(aes()) like this:
ggplot(example_data, aes(x = x, y = y)) + geom_point(aes(colour = color_column))
Which gives the same result.
Let me know if this doesn't get you all the way there and I'd be happy to help! If you need more help I would also recommend looking at "Scenario 2" from this link on how you can give us an example from your data to work with: https://reprex.tidyverse.org/articles/articles/datapasta-reprex.html