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