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