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