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