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