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