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