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