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