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