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