Whether or not this actually is the grave of Abu Waqas, the man who brought Islam to China in the 7th century and an uncle of the Prophet Mohammed, the sense of reverence here makes it worth seeking out. To find the tomb, go past the main prayer hall to a pavilion. There you'll find a path strewn with tinsel and incense leading to the grave, draped in cloth.
From Yuexiu Park metro exit B2, go north and take a left on Lanpu Lu. The entrance to the complex is at the end of the road.