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