Eevee's stats are the following:
Attack - BASE 55 MAX 229
Special Attack - BASE 45 MAX 207
As we can see the Special Attack is slightly lower than its Attack, so Swift with 60 base power will do much less damage than Return, which has 102 base power. Fighting types, which are Eevee's only weakness. Swift has infinite accuracy, meaning it will never miss, however Return also has 100 Accuracy, which means it will never miss unless a move such as Sand Attack hits it.
In conclusion, you might want to consider using Return as it has much more power and compliments Eevees higher Attack stat.