One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,3)(4,6,8,7)(9,10)(11,21,24,16)(12,25)(13,20)(14,19)(15,18)(17,28)(22,38,39,33)(23,32,30,36)(26,37,40,31)(27,34)(29,35)(2,6)(3,7)(4,8)(9,11)(10,16)(12,26)(13,23)(14,30)(15,24)(17,33)(18,21)(19,32)(20,36)(22,29)(25,37)(27,40)(28,39)(31,34)(35,38) involution — undirected(1,3,5,2)(4,6,8,7)(9,12)(10,17)(11,22)(13,29)(14,28)(15,27)(16,31)(18,35)(19,34)(20,25)(21,37)(23,40)(24,39)(26,30)(32,38)(33,36)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.