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