"says" is pronounced two ways. One with "ay" sounding like the "ai" in "said" and the other like the "ay" in "say". You properly want the former.

If you are asking how you transcribe the word 'says', I'd write it as /sez/.

For most U.S. English, I would transcribe it /sɛz/ -- the vowel is between /æ/ and /e/. As far as Suki's answer, this may just be a difference in transcription style, where monophthong /ɛ/ is written as /e/ to save fiddling with the keyboard.

/sez/