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