One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,8)(5,7)(9,10)(11,16)(12,17)(13,30)(14,31)(15,20)(18,27)(19,28)(21,39)(22,35)(23,40)(24,33)(25,37)(26,34)(29,38)(32,36) involution — undirected(2,6)(3,5)(7,8)(9,11)(10,16)(12,26)(13,21)(14,32)(15,25)(17,34)(18,35)(19,33)(20,37)(22,27)(23,29)(24,28)(30,39)(31,36)(38,40) involution — undirected(1,2,4,8)(3,6,5,7)(10,17)(11,21)(12,27)(13,29)(14,28)(16,33)(18,19)(20,38)(22,25)(23,32)(24,26)(30,31)(35,39)(36,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.