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