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