How to convert hex to ASCII
If you have a byte variable b, you can 


write(b) it as it is. if it is ASCII code of a readable character, the Serial Monitor will display it as that character, for example for 65 it will printt 'A'
print it as decimal number with print(b). for 65 it will print "65"
print it as hexadecimal number with print(b, HEX). for 65 it will print "41"
print it as a number in other base with print(b, base), for example print(b, 2) will print 1000001 if b is 65 in decimal