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