Sorry but that image is completely unintelligible with all the wires on top of each other. Don't bother with Fritzing. Just make a simple pencil drawing and post a photo of it.
If you use the internal pullup resistor with
pinMode (buttonPin, INPUT_PULLUP);
then you just need to connect your switch between the pin and GND. Note that it show LOW when pressed.
This is a simplified version of your program
void loop() {
buttonState = digitalRead(buttonPin);
if (buttonState == HIGH) {
pos = 45;
}
else {
pos = 0;
}
myservo.write (pos);
}
...R