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)(25,26,29,33)(27,30,34,39)(28,36,38,32)(31,37,40,35)(1,2)(3,7)(4,6)(5,8)(9,11,14,21)(10,15,17,19)(12,20,13,22)(16,23,18,24)(25,27,29,34)(26,30,33,39)(28,35,38,37)(31,32,40,36)(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)(28,37)(29,34)(30,36)(32,39)(33,40)(35,38)(10,17)(15,19)(16,18)(23,24)(25,27)(26,30)(28,35)(29,34)(31,36)(32,40)(33,39)(37,38) involution — undirected(2,6)(5,7)(9,13,14,12)(10,18,17,16)(11,20,21,22)(15,23,19,24)(27,34)(30,39)(31,40)(35,37)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.