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