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