So Vegeta in chapter #40 powers up to another form. Is this form supposed to be super saiyan blue evolution? Is it supposed to be a different form?
It is not acknowledged as a new transformation and Super Saiyan Blue Evolution is a new transformation. Vegeta was in his mastered Super Saiyan Blue form and reached a higher state of the form in terms of raw power(Comparable to SSJB Goku powering up against Jiren in Episode 122). Another reason for stating the same is because the Super Saiyan Blue Evolution was considered to be an anime-exclusive form.
However, it is important to note that we won't know the exact answer for the question until Toyataro makes any comment with regard to the same.