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