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