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