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