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