On an x-y grid, label them N-S, E-W, draw a line from the origin to the right and label it 425 (you are going East)

Question

From the end of that line draw a vertical line upwards of 40 (you are going North)

Use an approximate scale, realizing that 425 is just about 10 times "as long" as 40.
Join that endpoint to the origin.
This is your vector diagram and you should have a right-angled triangle where the hypotenuse is the magnitude.

The small angle at the origin will give you the direction angle of the plane.

A pilot heads his jet due east. The jet has a speed of 425mi/h relative to the air. The wind is blowing due north with a speed of 40mi/h. Find the direction of the jet. Confused about the angle. :( How do I sketch a diagram. Thanks a lot.

Thank you. But that is giving me the wrong answer.
From the diagram, tan(theta) = 40/425
so theta is 5.38.

The answer is 84.62, which I get when I use tan(theta) = 425/40
How is it possible? :(

we are both right, it all depends how you express the angle.

In navigation terms angles are stated clockwise from North.

the angle we have is 5.38 up from the "x-axis", which is 84.62 clockwise from North
(90 - 5.38 = 84.62)