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