Both canola oil and vegetable oil are quite similar, and it is totally possible for you to confuse them with one another if they were both next to each other on the counter. Both of these oils are pale yellow in color, neutral in flavor, inexpensive, and have high smoke points, which makes them good for high heat cooking, like frying.
Both of these oils can be used in place of the other, and while you might notice a slight difference in flavor if you tried just the oil, you shouldn't notice a difference in the flavor or texture of the final dish.
Canola oil is thought to be the healthier option of the two as it is lower in saturated fat than vegetable oil. Canola oil is also one of the few oils that is rich in omega-3 fat, and it can also help lower levels of bad cholesterol.
If saturated fat is a concern, reach for the canola oil. Otherwise, you can cook with either oil with great results.