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