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