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