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)(11,16)(12,25)(13,28)(14,19)(15,21)(17,24)(18,30)(20,26)(22,37)(23,33)(27,32)(29,34)(31,35)(36,40)(38,39) involution — undirected(2,6)(7,8)(9,11)(10,16)(12,26)(13,22)(14,23)(15,24)(17,21)(18,34)(19,33)(20,25)(27,40)(28,37)(29,30)(31,38)(32,36)(35,39) involution — undirected(1,3,5,4)(2,7,6,8)(9,12,26,11,15,23,14,24)(10,17,19,33,21,16,20,25)(13,29,40,38,31,27,30,22)(18,32,35,39,36,34,28,37)(1,4,5,3)(2,8,6,7)(9,13,26,40,15,31,14,30)(10,18,19,35,21,36,20,28)(11,22,23,29,24,38,12,27)(16,32,25,39,17,34,33,37)(2,6)(7,8)(9,14,15,26)(10,19,21,20)(11,23,24,12)(13,30,31,40)(16,33,17,25)(18,35,36,28)(22,29,38,27)(32,37,34,39)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.