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