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