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