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