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