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