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