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