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