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