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