In Derek Holt's answer to the question Generating pair for PSL(2,q)
He says that "the generators used by GAP (and Magma) are
$A_w := \left(\begin{array}{cc}w&0\\0&w^{-1}\end{array}\right)$, $B := \left(\begin{array}{cc}-1&1\\-1&0\end{array}\right),$
where $w$ is a primitive element of the field. The first generator has order $q-1$, and the second one order 3."
Is there a formula for the order of $BA_w$ (in terms of $w$ and $q$)?
Though, I'd settle for a formula in $q$ that gives the order of $BA_w$ for some primitive element $w$ of $\mathbb{F}_q$.
Does anyone have references for this?