Unless I'm missing something, they don't describe the size of the effects of personality that they found, just the strength of the correlations.
I'm not too clear on how to interpret hierarchical model coefficients, but they do give at least one description of effect size, on pg6:
These associations revealed clinically meaningful differences in weight. For example, participants who scored in the top 10% of Neuroticism's Impulsiveness weighed, on average, over 11 Kg more than those who scored in the lowest 10% of this trait. Likewise, participants who scored high on Conscientiousness's Order weighed about 4.5 Kg less than those who scored low on Order.
and pg8:
...In addition, the emotional aspects
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.