MySQL: Updating multiple columns using if else

I need help to set a mySQL update query for my little project like below:

UPDATE TABLE 
IF SUBSTRING_INDEX(REFERENCE, '_', -1)= 'A'  THEN
{
  TYPE = 1
  COLOR = 'BLUE'
}
ELSEIF SUBSTRING_INDEX(REFERENCE, '_', -1)= 'B'  THEN
{
  TYPE = 2
  COLOR = 'RED'
},
ID = SUBSTRING_INDEX(REFERENCE, '_', 1)
WHERE REFERENCE IS NOT NULL

In my table, there is a column REFERENCE which contains varchar like

A_1, A_2, A_10
B_1, B_4, B_12
etc...

where the character before the symbol '_' determines certain values for other columns like stated above. I am still fairly new to mySQL, so appreciates any help!